Automatically Balancing Register for HVAC Systems

ABSTRACT

Distributed nodes, such as intelligent register controllers, of a heating, ventilating and/or air conditioning (HVAC) system wirelessly communicate with each other on a peer-to-peer basis, forming a network, and collectively control the HVAC system, without a central controller. The intelligent register controllers collectively control the amount of conditioned air introduced into each region. Each node may base its operation at least in part on information about one or more (ideally all) of the other nodes. Each intelligent register controller automatically determines how much conditioned air to allow into its region, or how much return air to allow to be withdrawn from its region. Each register controller automatically determines when and to what extent to operate its respective controllable damper.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/940,432, filed Jul. 12, 2013 by Jon Barrett and Ronald Lingemann,titled “Automatically Balancing Register for HVAC Systems,” which is acontinuation of U.S. patent application Ser. No. 12/650,320, filed Dec.30, 2009 by Jon Barrett and Ronald Lingemenn, titled “AutomaticallyBalancing Register for HVAC System, which claims the benefit of U.S.Provisional Patent Application No. 61/203,911, filed Dec. 30, 2008 byJon Barrett and Ronald Lingemann, titled “Automatically BalancingRegister for HVAC Systems,” the entire contents of all of which arehereby incorporated by reference herein, for all purposes.

TECHNICAL FIELD

The present invention relates to control systems for heating,ventilating and air conditioning (HVAC) system and, more particularly,to systems that distribute control of an HVAC system among a pluralityof components, such as air supply registers, remote control units andthermostats, which communicate with each other.

BACKGROUND ART

Conventional forced air heating, ventilating and/or air conditioning(HVAC) systems have manually adjustable air register vents (air volumecontrol dampers) to control the amount of conditioned air introducedinto a room or other portion (for simplicity, collectively hereinafterreferred to as a “region”) of a building. In theory, the vents may bemanually adjusted upon installing the HVAC system or thereafter, so asto provide a correct amount of heated, cooled, filtered, etc.(collectively referred to herein as “conditioned”) air to each region.However, in practice, this seldom works properly. Usually, the registersare not adjusted at all, unless a region is intolerably cold or hot. Inaddition, it may be impossible to get enough conditioned air to a regionwithout adjusting the registers in every other region. Thus, manuallyadjusted registers rarely achieve a uniform comfort level throughout abuilding.

Manually adjusted registers can also waste energy. For example,introducing more conditioned air into a region than is necessary toachieve a comfortable temperature causes a heating or cooling plant tooperate longer or at a higher level than would otherwise be necessary.Even if registers have been adjusted to achieve a desired temperature inall regions, the registers may all be closed more than necessary, thusconstricting the air flow and increasing pressure in the ducts. Thiscauses the blower that moves the air to do more work than necessary,thereby wasting energy. In addition, the high air pressure in the ductsexacerbates any leaks in the ducts. Such duct leaks frequently allowconditioned air to enter an attic, crawl space or other region that doesnot need heating or cooling, thereby wasting energy.

Most homes with forced air HVAC systems have only one thermostat. Notonly does this mean that only one region actually maintains a desiredtemperature, it also makes it impractical to adjust the temperature indifferent rooms to suit the needs of occupants in those rooms.Consequently, room temperatures cannot be personalized.

To overcome some of these problems, some buildings are zoned. Each zonehas an associated thermostat to adjust the temperature in that zone. Inprivate homes, this is often implemented by installing a separate HVACsystem for each zone. Each zone has its own thermostat, fan, heatexchange, furnace or heat pump, cooling compressor, ducts, etc. This isnot only expensive; it can also be extremely wasteful of energy. Forexample, there is usually nothing to prevent one HVAC zone from heatinga portion of a building while another HVAC zone cools another, possiblyoverlapping, region of the building.

Attempts to solve the multi-zone HVAC problem often include installing acentralized control system coupled to various thermostats and, in somecases, to electrically or pneumatically operated dampers in the ducts.However, such centralized systems require installing wiring to thethermostats, dampers, etc., thereby increasing the difficulty ofretrofitting existing buildings. These systems are, therefore, moresuitable for new construction than for renovating existing buildings.Furthermore, once such a system is installed, it is difficult tosubdivide it into additional zones or to incrementally expand thesystem.

Prior art electronically controlled register vents for zone heating andcooling are described in U.S. Pat. No. 7,168,627 to Lawrence Kates, etal. A design for a multi-zone HVAC control system from an existingsingle-zone system using wireless sensor networks is described by AndrewRedfern, et al., in Smart Structures, Devices and Systems III, edited bySaid F. Al-Sarawi, Proc. of SPIE, Vol. 6414 (2007). The contents of boththese documents are incorporated herein by reference.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a system for controllingan HVAC system of a type having a plurality of HVAC vents. Each HVACvent may be disposed in a corresponding location in a building, such asto provide heat or air conditioning to a region of the building. Thesystem for controlling the HVAC system may include a correspondingplurality of intelligent controlled registers. Each intelligentcontrolled register is associated with a distinct one of the HVAC vents.Each one of the intelligent controlled registers is in communicationwith at least one other of the plurality of intelligent controlledregisters. Each intelligent controlled registers executes an autonomouslocal control program. The control program processes data provided byeach of the other intelligent controlled registers. Consequently, theplurality of intelligent controlled registers collectively control theplurality of HVAC vents on a peer-to-peer basis.

At least one of the plurality of intelligent controlled registers may bein wired or wireless communication with at least one other of theplurality of intelligent controlled registers.

Each one of the plurality of intelligent controlled registers may beconfigured to automatically determine presence of an intelligentcontrolled register that is not part of the system for controlling theHVAC system. If such an (uninstalled) intelligent controlled register isdetected, each intelligent controlled register of the HVAC controlsystem may automatically ascertain if the determined (uninstalled)intelligent controlled register should be added to the system forcontrolling the HVAC system. If so, the determined (uninstalled)intelligent controlled register is automatically added to the system forcontrolling the HVAC system. In other words, the network of intelligentcontrolled registers may automatically detect newly-installedintelligent controlled registers and automatically add them to thenetwork.

In another embodiment, a newly-installed intelligent controlled registerautomatically discovers a network of intelligent controlled registersand automatically installs itself. In this case, each one of theplurality of intelligent controlled registers is configured toautomatically determine presence of at least one other of the pluralityof intelligent controlled registers and automatically ascertain if theintelligent controlled register should be added to the system forcontrolling the HVAC system. If so, the intelligent controlled registeris automatically added to the system for controlling the HVAC system.

Each intelligent controlled register may be further configured toautomatically ascertain if the determined intelligent controlledregister should be added to the system for controlling the HVAC systemaccording to timing of air flow through the intelligent controlledregister and timing of air flow through the determined intelligentcontrolled register. Optionally or alternatively, the determination maybe made according to timing of light detected by the intelligentcontrolled register and timing of light detected by the determinedintelligent controlled register.

Each intelligent controlled register may be configured to detect othernewly-installed components of the network. For example, the intelligentcontrolled register may be configured to detect wirelessly automaticallydetermine presence of a thermostat that is not part of the system forcontrolling the HVAC system and automatically ascertain if thedetermined thermostat should be added to the system for controlling theHVAC. If so, the determined thermostat may be automatically added to thesystem for controlling the HVAC system.

The intelligent controlled register may be further configured toautomatically ascertain if the determined thermostat should be added tothe system for controlling the HVAC system according to timing of lightdetected by the thermostat and timing of light detected by theintelligent controlled register or according to timing of temperaturechanges detected by the thermostat and timing of temperature changesdetected by the intelligent controlled register.

Each intelligent controlled register may include a controllable damper.The intelligent controlled register may be configured such that, whenair flows through the controllable damper, at least one of the dampersof the plurality of intelligent controlled registers is fully open.

Each intelligent controlled register may be configured to wirelesslyreceive data from at least one other of the plurality of intelligentcontrolled registers and to forward at least some of the received datato a different at least one other of the plurality of intelligentcontrolled registers.

The HVAC system may include a ducted air handling system, a hydronicsystem and/or an electric resistance heating system. At least one of theplurality of intelligent controlled registers may be configured tocontrol a valve and/or to control an electrical switch of a proportionalcontrol device.

Each intelligent controlled register may include a motor coupled to acontrollable damper, a temperature sensor and a wireless transceiver forcommunicating with at least one other of the plurality of intelligentcontrolled registers. A controller may be coupled to the motor, to thetemperature sensor and to the transceiver. A power source may be coupledto the motor, to the transceiver and to the controller. The controllermay be configured to carry out processes, such as obtaining data fromthe temperature sensor and, via the wireless transceiver, data from atleast one other of the plurality of intelligent controlled registers.Using the obtained data, the controller may automatically determine adesired operation of the damper and drive the motor to cause the desiredoperation of the damper.

The power source may include an array of photovoltaic cells and/or afan-powered generator. The controllable damper of at least one of theplurality of intelligent controlled registers may include a valve. Eachof at least one of the plurality of intelligent controlled registers maybe mounted in an air register.

The motor may include a coil, and each intelligent controlled registermay further include a circuit board on which are mounted electroniccircuits implementing at least a portion of the controller. The coil ofthe motor may be mounted directly to the printed circuit board.

The circuit board may further include a plurality of electricallyconductive elements, and the motor may further include a conductiveelement spaced apart from the plurality of electrically conductiveelements to form a capacitor between the conductive element in the motorand one or more of the plurality of electrically conductive elements onthe printed circuit board. Capacitance of the capacitor depends on arotational position of the motor. The controller may be configured toascertain the rotational position of the motor based on the capacitanceof the capacitor.

The motor may include two sets of rotors and two sets of stators. One ofthe rotors and one of the stators may form a first “submotor” and theother one of the rotors and the other one of the stators may form asecond “submotor.” The two submotors may be disposed beside each otherand geared together.

The system for controlling an HVAC may further include a portable remotecontrol unit that includes a wireless transmitter and at least oneuser-actuateable control. The intelligent controlled register may beconfigured to receive a wireless signal from the portable remote controlunit. The controller may be configured to automatically determine thedesired operation of the damper based, at least in part, on the receivedwireless signal from the portable remote control unit.

The wireless transmitter of the portable remote control may include aline-of-sight wireless transmitter and/or a wireless line-of-sightdetector.

Each of the plurality of intelligent controlled registers may include avolume control damper configured to adjustably control an amount of heatdelivered through the intelligent controlled register. A motor may beunder control of the autonomous control program and mechanically coupledto operate the volume control damper. A printed circuit board mayinclude electronic circuits and windings of the motor. The motor may bea stepper motor.

The system for controlling an HVAC system may also include a volumecontrol damper position indicator that includes at least twoelectrically conductive elements spaced apart by a dielectric, such asair, thereby forming a capacitor. At least one of the at least twoelectrically conductive elements may be configured to move, with respectto the other of the at least two electrically conductive elements. Themovement may be in relation to the operation of the volume controldamper, so as to vary capacitance of the capacitor in relation to theoperation of the volume control damper.

Each of the plurality of intelligent controlled registers may beconfigured, absent an external input specifying a setpoint temperaturefor the corresponding location, so as to equalize temperatures of thelocations in the building.

Each of the plurality of intelligent controlled registers may beconfigured so as to maximize flow through at least one of the pluralityof intelligent controlled registers.

The HVAC system may include a blower and a heating or cooling unit. Atleast one of the plurality of HVAC vents may include a return vent, andat least one of the plurality of HVAC vents may include a supply vent.The system may further include a thermostat coupled to the HVAC systemso as to control the blower and coupled to at least one of the pluralityof intelligent controlled registers. Each of the plurality ofintelligent controlled registers may be configured to operate so as topermit air to be drawn in by an automatically selected at least one ofthe return vent. The air may be moved by the blower, and the air may beexhausted through an automatically selected at least one of the supplyvent, all without operating the heating or cooling unit. Thus, air maybe transferred from at least one automatically selected location in thebuilding (such as a room where the air is too hot) to another at leastone automatically selected location in the building (such as a roomwhere the air is too cold).

The HVAC system may include a blower controlled by blower control leadsand a heating or cooling unit controlled by heating or cooling unitcontrol leads. The HVAC control system may further include a thermostatcoupled to the HVAC system so as to control the blower and the heatingor cooling unit. The thermostat may be further coupled to at least oneof the plurality of intelligent controlled registers. The thermostat maybe configured to automatically identify: power leads connected to thethermostat, the blower control leads connected to the thermostat and theheating or cooling unit control leads connected to the thermostat.

An embodiment of the present invention provides a system for controllingan HVAC system of a type having a plurality of HVAC vents. Each HVACvent may be disposed in a corresponding location in a building, such asto provide heat or air conditioning to a region of the building. TheHVAC control system may include a corresponding plurality of intelligentcontrolled registers. Each intelligent controlled register may beassociated with a distinct one of the HVAC vents. Each intelligentcontrolled register may include a motor coupled to a controllabledamper, a a temperature sensor and a a wireless transceiver forcommunicating with at least one other of the plurality of intelligentcontrolled registers. A controller may be coupled to the motor, to thetemperature sensor and to the transceiver. A power source may be coupledto the motor, to the transceiver and to the controller. The controllermay be configured to carry out processes, such as obtaining data fromthe temperature sensor and, via the wireless transceiver, data from atleast one other of the plurality of intelligent controlled registers.Using the obtained data, the controller may automatically determine adesired operation of the damper; and drive the motor to cause thedesired operation of the damper.

Yet another embodiment of the present invention provides a method forcontrolling an HVAC system of a type having a plurality of HVAC vents,in which each HVAC vent is disposed in a corresponding location in abuilding. The HVAC control system may include a corresponding pluralityof intelligent controlled registers. Each intelligent controlledregister may be associated with a distinct one of the HVAC vents. Datais obtained from a temperature sensor. In addition, data is wirelesslyobtained from at least one other of the plurality of intelligentcontrolled registers. The obtained data is used to automaticallydetermine a desired operation of a damper. A motor is driven to causethe desired operation of the damper.

Presence of an intelligent controlled register that is not part of thesystem for controlling the HVAC system may be wirelessly automaticallydetermined. The determined intelligent controlled register may beautomatically added to the system for controlling the HVAC system.

Data may be wirelessly received from at least one other of the pluralityof intelligent controlled registers. At least some of the received datamay be forwarded to a different at least one other of the plurality ofintelligent controlled registers.

Electrical power may be generated with an array of photovoltaic cellsand/or with a fan-powered generator at at least one of the plurality ofHVAC vents. The motor may be powered at least partially by the generatedelectrical power.

The motor may adjust vanes of an air volume control damper, adjust avalve, adjust an electrically controlled switch and/or adjust anelectrically controlled proportional control device.

A wireless signal may be received from a portable remote control unit.The received wireless signal may be used to obtain the data toautomatically determine a desired operation of a damper.

Another embodiment of the present invention provides an intelligentcontrolled register for use in an HVAC system of a type having aplurality of HVAC vents. Each HVAC vent may be disposed in acorresponding location in a building. The intelligent controlledregister includes a motor coupled to a controllable damper, atemperature sensor, and a wireless transceiver for communicating with atleast one other intelligent controlled register, A controller may becoupled to the motor, to the temperature sensor and to the transceiver.A power source may be coupled to the motor, to the transceiver and tothe controller. The controller may be configured to carry out processes,such as obtaining data from the temperature sensor and, via the wirelesstransceiver, data from at least one of the at least one otherintelligent controlled register. The controller may use the obtaineddata to automatically determine a desired operation of the damper anddrive the motor to cause the desired operation of the damper.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood by referring to thefollowing Detailed Description of Specific Embodiments in conjunctionwith the Drawings, of which:

FIG. 1 is a schematic diagram of an HVAC system in which embodiments ofthe present invention may be practiced;

FIG. 2 is a perspective view of the front of an intelligent controlledregister, according to an embodiment of the present invention;

FIG. 3 is a perspective view, from the right, of the rear of theintelligent controlled register of FIG. 2;

FIG. 4 is a perspective view, from the left, of the rear of theintelligent controlled register of FIG. 2;

FIG. 5 is an exploded perspective view of the intelligent controlledregister of FIG. 2;

FIG. 6 is a schematic block diagram of the intelligent controlledregister of FIG. 2;

FIG. 7 is a schematic circuit diagram of a power supply for thecontrolled register of FIG. 2, according to an embodiment of the presentinvention;

FIG. 8 is a schematic block diagram of an HVAC remote control unit ofFIG. 1, according to an embodiment of the present invention;

FIG. 9 is a flowchart illustrating a temperature control process,according to an embodiment of the present invention;

FIG. 10 is a flowchart illustrating another temperature control process,according to an embodiment of the present invention;

FIG. 11 is a flowchart illustrating operation of the controlled registerof FIG. 2, according to an embodiment of the present invention

FIG. 12 is a schematic timing diagram of a communication protocol amongthe controlled registers of FIG. 1, according to an embodiment of thepresent invention;

FIGS. 13A and 13B collective contain a flowchart illustrating operationsperformed by the controlled register of FIG. 2 upon first beinginstalled or upon recovering from a power-down condition, according toan embodiment of the present invention;

FIG. 14 is a flowchart illustrating operations performed by theintelligent controlled register of FIG. 2 for forming a network withother intelligent controlled registers, according to an embodiment ofthe present invention;

FIG. 15 is a flowchart illustrating operations performed by theintelligent controlled register of FIG. 2 for joining an existingnetwork of other intelligent controlled registers, according to anembodiment of the present invention;

FIG. 16 is a perspective view of an integrated motor and sensorassembly, according to an embodiment of the present invention;

FIG. 17 is an exploded perspective view of the integrated motor andsensor assembly of FIG. 16;

FIG. 18 is another exploded perspective view of the integrated motor andsensor assembly of FIG. 16, showing sensor pads, according to anembodiment of the present invention;

FIG. 19 is an exploded perspective view of the integrated motor andsensor assembly of FIG. 16, showing the sensor pads as the motor isrotated to a different position;

FIG. 20 is a schematic diagram of another HVAC system in whichembodiments of the present invention may be practiced;

FIG. 21 is a schematic block diagram of an exemplary data packet,according to an embodiment of the present invention;

FIG. 22 is a schematic block diagram of an exemplary a device settingsdata packet, according to an embodiment of the present invention;

FIG. 23 is a schematic block diagram of an exemplary a remote commandpacket, according to an embodiment of the present invention;

FIG. 24 is a schematic block diagram of an exemplary remote standardupdate packet, according to an embodiment of the present invention;

FIG. 25 is a schematic block diagram of an exemplary remote settingsupdate packet, according to an embodiment of the present invention; and

FIG. 26 is a schematic block diagram of an exemplary device informationtable, according to an embodiment of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Definitions. As used in this description and the accompanying claims,the following terms shall have the meanings indicated, unless thecontext otherwise requires:

“HVAC system” means a system that provides heat, ventilation and/or airconditioning to a building or a portion of a building. An HVAC systemmay provide one or more such functions.

“Array of photovoltaic cells” means one or more cells that convert lightinto electricity by the photovoltaic effect.

“Hydronic” means the use of water as a heat-transfer medium in a HVACheating or cooling system. Examples of heating systems include steam andhot-water radiators. In large-scale commercial buildings, such ashigh-rise and campus facilities, a hydronic system may include a chilledwater loop and a heated water loop to provide for both heating and airconditioning. Chillers and cooling towers may be used separately ortogether to provide water cooling, while boilers may be used to heatwater.

A “controllable damper” is a device that controls heat transfer into orout of a region associated with a location in a building. In anair-based HVAC system, a controllable damper may be implemented by anadjustable register in a vent, such as by an adjustable vane. Theregister may be binary, i.e., the register may have exactly two possiblestates (such as partially or fully closed and partially or fully open),or the register may be step-wise or continuously variable between twoextreme states, i.e., the register may have more than two possiblestates. In a hydronic HVAC system or in an electric resistance heatingsystem, a controllable damper may be implemented by an adjustableregulator, similar to that used in an air-based HVAC system, to controlair flow through or near a heat exchanger, such as a radiator.Optionally or alternatively, a hydronic controllable damper may beimplemented by a valve to control flow of water, steam or another fluid.

Embodiments of the present invention provide methods and systems forcontrolling HVAC systems in a distributed manner. In variousembodiments, such control is achieved by providing intelligent registercontrollers that operate in a peer-to-peer manner. FIG. 1 is a schematicdiagram of an air-based HVAC control system 100 (enclosed within adashed line) that includes components, and that performs processes, inaccordance with an embodiment of the invention. Each intelligentregister controller automatically determines how much conditioned air toallow into its region, or how much return air to allow to be withdrawnfrom its region, based on information collected by the registercontroller, such as: current temperature of the region; desiredtemperature of the region; calculated amount of conditioned air requiredto change the region's temperature to the desired temperature;temperature of conditioned air begin supplied by a duct to the register;current time, day of week, vacation or other schedule data; temperaturesof other regions and their respective desired temperatures; calculatedamounts of air required to be supplied or withdrawn by the othercontrolled registers to change their respective regions' temperatures totheir desired temperatures; or combinations thereof. However, as will bedescribed below, other embodiments of the present invention employsimilar components and similar principles to control other types of HVACsystems, such as hydronic or electric resistance heating systems.

As shown in FIG. 1, a furnace, heat pump, cooler and/or other device orcombination of devices 103 heats or cools air that is then moved throughthe HVAC system by a blower 106. (The blower 106 may be coupled to theinput, rather than to the output, of the heating/cooling device 103.) Aconventional thermostat 108 and a conventional HVAC control unit 109control operation of the heating/cooling device 103 and the blower 106.Optionally or alternatively, the air may be filtered and/or exchangedfor outside air, etc. (not shown). For simplicity of explanation, theair is referred to herein as being “conditioned,” regardless of how theair is treated, i.e., heated, cooled, etc.

The conditioned air is carried by a series of ducts 110 to a pluralityof HVAC vents, such as supply registers 113, 116, 120 and 128. Ofcourse, there may be more or fewer supply registers and more or lesscomplex duct work than are shown in FIG. 1. The supply registers 113-120and 128 may be disposed in various locations of a building, such as inwalls of rooms of a house, in walls or ceilings of corridors or inceilings of an office building. One or more of the supply registers113-120 and 128 may be in a given room. Each supply register 113-120 and128 may introduce conditioned air into its respective region. Returnregisters 123, 126 and 129 and an associated return duct 130 return airto the heating/cooling device 103. Of course, there may be other numbersof return registers and more or less complex return duct work.

One or more of the supply registers 113-120 and 128 may include arespective intelligent register controller 133, 136 and 140. Eachregister controller 133-140 operates a controllable damper to controlthe amount of conditioned air the corresponding supply register 113-120allows into its respective region. In addition, each register controller133-140 measures the temperature of its respective region.

Optionally, one or more of the return registers 123-129 also includes aregister controller 143 and 146 that controls the relative amount of airallowed to be drawn from its respective region back into the HVACsystem. A register 113-120 and 123-126 that is equipped with a registercontroller may be referred to herein as an “intelligent controlledregister” or simply a “controlled register.”

The amount of air permitted to flow through a register 113-126 may becontrolled by any suitable structure, such as a motorized adjustablevane or a set of vanes in the register. Each controlled register'scontroller 133-146 operates its respective vane(s).

The controlled registers 113-126 and the register controllers 133-146are not, however, centrally controlled. Furthermore, the registercontrollers 133-146 need not necessarily be connected to theheating/cooling system thermostat 108, the blower 106, the HVAC controlunit 109 or the heating/cooling device 103. The register controllers133-146 form a wireless communication network, by which the registercontrollers 133-146 (and optionally other components of the HVAC controlsystem 100, collectively referred to as “nodes” of the network) canprovide information to other register controllers 133-146 in thenetwork.

Each register controller 133-146 automatically determines how muchconditioned air to allow into its region, or how much return air toallow to be withdrawn from its region, based on information collected bythe register controller 133-146. This information may include: thecurrent temperature of the region; a desired temperature of the region;a calculated amount of conditioned air required to change the region'stemperature to the desired temperature; temperature of conditioned airbegin supplied by a duct to the register; current time, day of week,vacation or other schedule data; temperatures of other regions and theirrespective desired temperatures; calculated amounts of air required tobe supplied or withdrawn by the other controlled registers to changetheir respective regions' temperatures to their desired temperatures;charge state of a battery powering the register controller 133-146 or acombination thereof. Based on the determination of the amount ofconditioned air required, each register controller 133-146 automaticallydetermines when to operate its respective controllable damper and anextent to which the controllable damper should be opened or closed, andthe register controller 133-146 operates the controllable damper. Itshould be noted that a register's controllable damper may be opened foronly a portion of the amount of time the blower 106 is operating.

Each node of the network may base its operation at least in part oninformation about one or more (ideally all) of the other nodes in thenetwork. Thus, the intelligent register controllers 133-146 (andoptionally other nodes) of the network collectively control the amountof conditioned air introduced into each region. This control function isdistributed across the network of intelligent controlled registers.Significantly, this control function does not use a central controller.That is, no central controller instructs each register controller howand when to operate its controllable damper. None of the registercontrollers 133-146 is a “master” that controls the other registercontrollers. A remote control unit 150-153 (described in more detailbelow) or a central node, such as a computer 156, may provideinformation about desired temperatures, set-back times, etc. However, bysending this information, the remote control unit 150-153 or thecomputer 156 does not command a register controller 133-146 to open orclose its controllable damper. Instead, the register controllers 133-146use this information as part of their calculations to determine when andto how to operate their respective controllable dampers.

Each register's controller 133-146 includes a wireless transceiver thatenables the register controller 133-146 to wirelessly communicate withother register controllers 133-146 in nearby registers 113-126. Theducts 110 and 130 may act as waveguides to carry wireless signals orotherwise facilitate the wireless communication among the registercontrollers 133-146. Nevertheless, all the register controllers 133-146may not be able to directly wirelessly communicate with all the otherregister controllers 133-146, due to limitations on transmitter power,distances involved, electromagnetic interference (EMI), battery chargelevel, etc. Therefore, each register controller 133-146 relays data itreceives from other register controllers 133-146 to yet other registercontrollers 133-146. Thus, each register controller 133-146 mayultimately receive information about every other register controller133-146 in the HVAC control system 100, albeit not necessarily directlyfrom the register controller about which the information is provided.

Any number of (including zero) hand-held remote control units,exemplified by remote control units 150 and 153, may be used. Theseremote control units wirelessly communicate with register controllers133-146 in nearby registers 113-126, although the communication betweena remote control unit 150-153 and a register controller 133-146 mayinvolve a different medium (such as infrared light-based communicationor radio frequency (RF)-based communication) or a different frequencythan the communication among the register controllers 133-146. Eachremote control unit 150-153 includes a keyboard and a display, by whicha user may instruct the HVAC control system 100 or a component thereofto change a parameter, such as a desired temperature in the region wherethe user is located. Optionally, one or more of the remote control units150-153 may be attached to fixed locations, such as on walls, in thebuilding.

Optionally, one or more network thermostats, exemplified by networkthermostat 160, may be included in the HVAC control system 100. Thenetwork thermostat 160 may be installed in a region, such as mounted ona wall of a room, to allow the user to directly set a desiredtemperature or temperature program for the near-by area. Like theregisters, the thermostats automatically detect and connect to anexisting network, but unlike the registers, never create a new network.The primary function of the network thermostat is to inform theregisters of the desires of the system user, and to provide sufficientinformation on its environment so that each register may determine if itis to use the set point information. For example the network thermostatmay record and report to the network the times of sudden increase ordecrease in light level, presumably caused by someone turning on a lightor opening a door or a window shade. Any register observing the sameenvironmental changes would then assume that it is near that thermostat,and should use that thermostats temperature set point as its temperaturegoal. The network thermostat 160 may be powered by a photovoltaic celland/or a conventional user-replaceable battery.

Optionally, one or more of the network thermostats, exemplified bynetwork thermostat 163, may be connected to (or replace) the thermostat108. Optionally or alternatively, the network thermostat 163 may beconnected to the HVAC control 109, or the network thermostat 163 may beotherwise connected to the HVAC system. In either case, the networkthermostat 163 may control operation of the heating/cooling device 103and/or the blower 106. For example, if one region is warmer than itneeds to be, while another region is cooler than it needs to be, theHVAC control system 100 may move some air from the warm region to thecool region by opening controllable dampers in the respective regions,closing other controllable dampers, and causing the blower 106 (but notthe heating/cooling device 103) to operate. One or more controllablereturn registers 123-126 proximate the region from which air is to bemove may be opened while controllable return registers proximate otherregions may be closed, and one or more controllable supply registers113-120 proximate the region to which the air is to be moved may beopened while controllable supply registers proximate other regions maybe closed. A network thermostat that is electrically connected to thethermostat 108, etc. may be powered by the HVAC system and need not,therefore, necessarily include a photovoltaic cell.

As noted, the register controllers 133-146 receive information about theother register controllers 133-146. Using this information, as well asinformation about a desired temperature in the region serviced by agiven register controller 133-146, the register controller 133-146determines a desired operation of an controllable damper in itscorresponding controlled register, and the register controller 133-146drives a servo, such as a stepper motor and position sensor, to causethe desired operation of the damper. Thus, the register controller133-146 controls the amount of conditioned air introduced into itsregion or withdrawn from its region, in order to meet (as well aspossible, given the capacity of the heating/cooling device 103 and theblower 106, ambient conditions, etc.) the desired temperature. Absentinformation from any remote control unit 150-153, computer 156 ornetwork thermostat 160-163 about a desired temperature, the registercontrollers 133-146 may operate so as to equalize the temperatures ofall the regions. Thus, in an installation with a single conventionalHVAC thermostat 108, which is not connected to the network of registers,and the addition of only the controlled registers 113-126 may operate toequalize the temperature in all the rooms of a house. This feature,alone, provides a significant improvement in comfort level and energysavings (by avoiding over-heating one or more of the rooms to satisfythe thermostat 108) over prior art HVAC control systems.

Installation

One or more components of the HVAC control system 100 may be installedin a new HVAC system, or one or more components of the HVAC controlsystem 100 may be retrofitted into an existing structure. In eithercase, later, addition components of the HVAC control system 100 may alsobe installed.

Upon being installed, each new component attempts to communicate withother components of the HVAC control system 100 that are within range ofthe newly installed component's wireless transceiver. The newlyinstalled component then identifies which, if any, of these othercomponents are part of the same HVAC system as the newly installedcomponent. (It should be noted that there may be components installed inunrelated HVAC systems that are within wireless communication range,such as HVAC systems in nearby homes or on other floors of a multi-storybuilding, and the newly installed component should ignore theseunrelated components.) A process of discovering other components isdescribed in the context of installing a register controller; however, asimilar process may be used by other types of components.

A newly installed register controller 133-146 monitors thecommunications of other register controllers that are within range ofthe newly installed register controller's wireless transceiver. Bycomparing environmental data received from the discovered network, suchas the time that air flow starts and stops, with its own measurements,the register determines if it should, or should not join that network.Components with photovoltaic cells may optionally or alternatively notetimes at which light intensities (presumably due to the apparentmovement of the sun or artificial lighting) are high or low andcorrelate the detected lighting level patters with other light-sensitivecomponents, as described in more detail below. If the discovered networkis in the same environment as the new register, it joins that network.Register controllers 133-146 may routinely send information about theirrespective air flow times, light level patterns, etc., or the registercontrollers 133-146 may be queried by the newly installed registercontroller for this information.

Similarly, the network thermostats 160-163 should experienceenvironmental changes that correlate well with nearby registers.

Although in some embodiments components use timings of air flows ortemperature changes to facilitate automatically discovering othercomponents, this automatic discovery may be based on timings of otherenvironmental changes, such as humidity or light. For example, as notedbelow, the controlled registers may include photovoltaic cells to powerthe register controllers 133-146. Using timings and strengths of signalsfrom these photovoltaic cells, the register controllers 133-146 maycorrelate times at which relatively strong light, such as sunlight,shines on the photovoltaic cells, or times at which relative weak light,such as artificial light from interior lamps, or no light shines on thephotovoltaic cells.

If the newly installed register controller 133-146 fails to find anetwork using the same HVAC system, the newly installed registercontroller 133-146 forms a new network and operates alone, until anotherregister controller 133-146 or network thermostat 160-163 that is partof the same HVAC system comes within range and joins its network. Thenetwork thermostats 160-163 perform similar operations upon theirinstallation.

Thus, each register controller 133-146 and network thermostat 160-163 isessentially self-installing, in that no user involvement is required tointerconnect the register controllers 133-146 or the network thermostats160-163 to each other. The user only needs to put the registers andthermostats where he wants them. The HVAC system 100 facilitatesincremental growth; components may be added at any time, and not allregister need to be equipped with register controllers. Consequently, abuilding owner may install register controllers in a few selectedlocations, such as rooms that are chronically too hot or too cold, so asto enhance comfort in these regions. In another scenario, the buildingowner may install register controllers 133-146 in locations that arefrequently unoccupied, so as to save energy by minimizing the amount ofconditioned air supplied to these regions. While installation ofregister controllers 133-146 in less than all the registers of an HVACsystem may not be optimum, such an installation may provide the greatestsaving or comfort improvement for the corresponding investment, i.e.,the cost of the controlled registers. A number of features makeautomatic self-installation possible. Among these are aself-initializing communications network, an ability to determine if twocomponents are in the same system, an ability to determine relativelocation and elimination of a fixed temperature target (replaced byequalizing temperature via an assumed set point).

Intelligent Register Controller

The main functions of the intelligent register controller 133-146 are:dynamically control the amount of air allowed to pass through anassociated register 113-126; measure air temperature in the associatedregion (room); measure temperature of air in the associated duct;identify, communicate with and coordinate with other network components;maintain a clock/calendar; generate electrical power to operate theregister controller; and communicate with one or more remote controlunits 150-156.

FIG. 2 is a perspective view of the front of an exemplary register 200.Much of the face 203 of the register 200 may be covered by, orconstructed of, photovoltaic cells, exemplified by photovoltaic cells206. An indicator, such as a light-emitting diode (LED) 210, may beincluded to display status information. A circuit board 213 may beattached to the rear, or another convenient portion, of the register200. The circuit board 213 includes a processor, power control circuits,etc., as described herein.

FIG. 3 is a perspective view of the rear of the register 200. Acontrollable damper, here exemplified by two counter-rotating vanes 300and 303, is attached to the register 200 to control air flow through theregister 200. The controllable damper may be operated by a servo, suchas a stepper motor and position sensor (not visible). The controllabledamper may be constructed so as to hold its position, such as byfriction, without use of power between times the positions of the vanes300 and 303 are changed by the servo motor 306. A high pole count motor,such as a stepper motor, may be used. Natural magnetic detents providedby the poles may be used to hold the controllable damper in place. Theposition of the controllable damper may be manually adjusted by a user,such as by a thumb wheel (not shown), in case the register controllerfails. Return registers 123-126 should be equipped with controllabledampers that fail in an open state, so that if such a register fails,air may still return via the register.

FIG. 4 is another perspective view of the rear of the register 200, inwhich the circuit board 213 may be more clearly seen. FIG. 5 is anexploded view of the register 200. In the embodiment shown in FIG. 5, atransparent front plate 500 covers the photovoltaic cells 206. Aperforated grill 503 disperses air flowing through the grill 200. Theservo motor 506 is visible in FIG. 5.

FIG. 6 is a schematic block diagram of one of the intelligent registercontrollers 133-146. The register controller may be implemented byelectronic components on, or connected to, the circuit board 213. Thephotovoltaic cells 206 are connected to a power supply 600, which isdescribed in more detail below. The power supply 600 may include arechargeable battery, a super capacitor or another suitable energystorage device for powering the remaining circuits when the photovoltaiccells 206 are insufficiently illuminated to directly power the circuits.The register controller may communicate with other network nodes via awireless transceiver 603, such as an RF transceiver. Among otherinformation, the intelligent register controller may inform other nodesof the amount of energy in its energy storage device, so that networktasks may be allocated to nodes having the greatest power reserves.

An infrared (IR) transceiver (or, in some cases, only a receiver ortransmitter) 606 facilitates wireless communication between the registercontroller and a remote control unit 150-153. One or more temperaturesensors 610, such as one or more thermistors, silicon diodes or anyother suitable temperature-sensitive components, are located so as to beexposed to air flowing through the register 200. A controller 613controls operation of the remaining components of the registercontroller. The controller 613 may be implemented with a processor 620executing instructions stored in a memory 622. A clock 626 enables thecontroller 613 to keep track of time and date although, as noted below,the clock may keep track of time according to an arbitrary time zone,such as a time zone based on 12 o'clock corresponding to high noon orhigh moon, as detected by bright light illuminating the photovoltaiccells.

To minimize power consumption, the baffle should maintain its positionwithout power use. In addition, a user should be able to manually adjustthe position of the baffle, in case of a failure of the register. In oneembodiment, a high pole count motor, such as a stepper motor, drives thebaffle without gearing. The natural magnetic detent properties of such amotor may be used to hold the baffle in place. The baffle, motor, andmanual adjustment wheel may be on a common shaft. In the case ofmultiple baffle blades, which may be used to reduce the depth of theregister, one blade may be on the common shaft, and the other blades maybe driven by gears or a linkage.

To reduce the parts count, wiring and cost of the stepper motor baffledrive, part of the motor and position sensing device may be mounted onthe main printed circuit board. Windings of the motor may be mounted onthe circuit board, and permanent magnet pole pieces may be attached tothe shaft. A (plated through) hole in the circuit board may provide ashaft bearing to keep the motor parts aligned. A position sensor mayalso be a part of the board. A capacitance sensor may be formed by padson the board and rotating segmented plates attached to the shaft. Themoving permanent magnet pole piece may be either in the shape of a cupthat surrounds a puck-shaped coil assembly attached to the circuitboard, or the rotating permanent magnet poles may be in the center of astationary ring of a coil assembly. In either case, the moving capacitorplates may be attached to the pole piece assembly. The capacitor plates,or the entire baffle-shaft assembly, may be spring mounted to force theminto contact with the board, and one of the plates (stationary ormoving) may be covered with a thin insulator. The moving plates may beactivated by a stationary plate segment on the circuit board, so that nowires to the moving parts may be required.

The manual adjustment of the baffle may be made using a wheel on thebaffle shaft that has a large enough diameter so that a chord of thewheel protrudes through a slot in the face of the register. The shaftfrom the baffle to the wheel may be made slightly flexible, so thatpushing the wheel into the face of the register (caused, for example, bysomeone stepping on the register) does not cause damage.

Clock

Each register controller 113-146 maintains several clock times andseveral states related to these times. The most fundamental time in eachregister controller 113-146 is a unit time (UT) clock. This is a countthat is initialized to zero when the register controller 113-146 ismanufactured and is incremented at a fixed rate as long as the registercontroller's processor 620 is powered up. This time has enoughresolution to record the time of events as accurately as needed, such aswithin 1/256 second. The accumulator for this time has enough bits, suchas 40 bits, that it will not overflow during the expected lifetime ofthe register controller. If the processor 620 detects that it will soonrun out of power, this clock is saved in nonvolatile memory.

As part of the state for this clock, there are three other saved values.One value is the current status of the UT: Resetting or Valid. Thisstatus bit is set to “Resetting” from the time that the component savesthe UT in preparation for a complete shutdown, due to low power, untilpower is restored and accumulation resumes. When the UT is againrunning, its state is changed to “Valid.” The second status datum is thevalue of the UT at the previous power failure, or Last Crash Unit Time(LCUT). This value is initialized at the time of manufacture to zero andis set to the value of the saved UT value when the UT is restarted, andmay in fact be the value in nonvolatile memory saved at the time of apower failure. The time since the last power failure may be calculatedby subtracting LCUT from the current UT. The processor can ascertain ifa stored UT value is valid as a time span measurement by checking thatthis value is greater than the LCUT. The third value is a count of thenumber of times that the LCUT has been changed, i.e. the number ofprocessor power failure crashes. This last value is used to determine ifa register controller is having frequent power failures and shouldperhaps be up graded from a light powered register controller to a lightand wind or externally powered register controller.

The second “time” each register controller maintains is network time(NT). This is in fact a correction from UT to a time consistent amongthe members of a network. It is set to the UT of the oldest member of anetwork. Each network component maintains a signed value which, whenadded to its UT, gives NT and a status value which is set to Valid aftera register joins a network and is given or gives the NT. To preventdisagreements in NT when a new component joins a network, there is aprocess that first has all components in the network set NT as notvalid. The process then distributes the new NT, from which eachcomponent computes its correction value, and then the process sets NT asvalid.

The last time the register controller maintains is real time. This isalso kept as an offset from UT, and a status. The offset is the numberof that must be added to UT to produce the local real time in secondssince a predetermined time, such as the beginning of the year 2000. Thisvalue has at least two possible statuses: valid and not valid. Thestatus is initialized to not valid and reset to not valid on any crash.The status is set to valid when the register controller is informed ofthe local time by a remote control unit 150-153 or from another node ofthe network.

Using the temperature sensor 610, the register controller may ascertainthe temperature of conditioned air being delivered to the region. Inaddition, the register controller may ascertain the speed of the airbeing delivered, such as by forcing a known electric current through thethermistor for a short time, thereby heating the thermistor above thetemperature of the conditioned air, and then measuring the amount oftime required for the temperature of the thermistor to drop apredetermined amount, such as to one-half the difference between theheated temperature and the flowing air temperature.

A relationship between air flow speed and temperature drop, as afunction of time, may be determined experimentally or algorithmicallyusing known characteristics of the thermistor. Data representing thisrelationship or representative air speed-temperature drop time valuepairs may be stored in a table, such as in the memory 622 of thecontroller 613. Optionally or alternatively, this relationship may bestored as a mathematical function in the memory 622. The table orfunction may be used to calculate the air flow speed from thetemperature drop time.

After the blower 106 has stopped operating and a suitable amount of timehas passed for temperatures within the register to stabilize with theregion, the temperature sensor 610 may be used to measure thetemperature of the region, thus obviating or reducing the need for athermometer in the region.

Optionally or alternatively, the conditioned air flow rate may bemeasured by another sensor (not shown), such as two electricallyconductive pads. One of the pads may be fixed on the circuit board 213,and the other pad may be attached to a flexible vane within the path ofthe conditioned air flow. When the conditioned air flows, it deflectsthe flexible vane an amount proportional to the air flow rate. Thecontroller 613 measures capacitance between the two pads when theconditioned air flows and when it does not flow. The difference in thetwo capacitance measurements indicates the amount of vane deflectionand, therefore, the air flow rate.

Thus, the controller 613 may ascertain three pieces of information:region temperature, conditioned air temperature and conditioned air flowrate.

By testing for air flow at frequent intervals, the controller 613 maymeasure the amount of time that the heating/cooling device 103 and/orthe blower 106 operate, i.e., an HVAC system “run-time.” However, allthe controlled registers 112-126 experience air flows at nearly the sametime. Therefore, all the register controllers 133-146 need notsimultaneously perform their own HVAC system run-time measurements.Instead, only one or a small number of the register controllers 133-146may need to perform the HVAC system run-time measurement at any point intime, and the run-time information may then be provided to the otherregister controllers 133-146 in the network. Register controllers133-146 not performing the HVAC system run-time measurement may be ableto enter a low power state, thereby conserving energy. The task ofmeasuring HVAC system run-time may be allocated in a round-robin fashionamong the register controllers 133-146. Optionally or alternatively,this allocation may be modified so as to exclusively or more heavily useregister controllers 133-146 having the greatest power reserves (i.e.,the highest levels of charge in their batteries.

The HVAC system run-time and information about differences betweentemperatures of conditioned air supplied to regions and the regions'temperatures may be used by one or more nodes of the network tocalculate the amount of energy delivered through the registers 112-126.If the energy used by the HVAC system is also known, the efficiency ofthe HVAC system can be calculated. The energy used by the HVAC systemmay be input by a user, such as by entering data from energy bills.Alternatively, if the power rating (ex., the kilowatt rating of an airconditioning unit) of the HVAC system components, i.e., theheating/cooling device 103 and the blower 106, are known, the amount ofenergy used by the HVAC system may be calculated by multiplying thepower rating by the amount of time the HVAC system components operate.

Even if the amount of energy used by the HVAC system is not known,relative efficiencies of providing conditioned air to various regions,i.e., through particular controlled registers 113-120, may be calculatedby nodes of the network. If one or more of these regions or registers112-120 operates less efficiently than the others, a node may notify auser, such as by sending a message to a remote control unit 150-153 orto the computer 156 or by illuminating the indicator 210 on theregisters 200. This may alert the user to improve thermal insulation ofthe region and/or decrease infiltration of outside air into the region.Optionally or alternatively, the user may be able to make informeddecisions regarding continued heating or cooling of the region, in lightof the amount of use the region receives, relative to the amount ofenergy used to heat or cool the region. Similarly, a sudden decrease inthe efficiency of a region may be caused by a window having been leftopen, and the user may be similarly alerted.

Optionally, each controlled register 113-126 may be equipped with athermal infrared sensor 212 (FIGS. 2, 5 and 6), positioned and orientedso as to have a view into the region serviced by the controlled register113-126. This sensor measures black body radiation from the nearestsolid object in front of it. The infrared sensor 212 accepts radiationthrough a window on the face 500 of the register 200, so if the register200 is mounted in a floor, the infrared sensor 212 may measure thetemperature of a ceiling. This measurement can be correlated with theregion air temperature measurement made using the temperature sensor610. Using this correlation, the infrared temperature may be used tocompute the region's room air temperature, even when air is passingthrough the register 200.

Region occupancy information may be advantageously used by thecontroller 613 to save energy by providing less than the usual amount ofconditioned air into a region that has not been occupied for some time.The controller 613 may employ one or more of several methods toascertain region occupancy. For example, the infrared sensor 212 may beused to detect when a person or animal briefly passes in front of theregister 200. Optionally or alternatively, the photovoltaic cells 206may be used to detect that room lights are on, which may indicate thatthe room is occupied. A shadow, for example a shadow cast by a passingoccupant, briefly passed over the photovoltaic cells 206 may alsoindicate the region is occupied. In some cases, opening or closing adoor to a region alters airflow into or out of the region. Thus, achange in the air flow through the controlled register 113-126, withoutthe controller 613 having caused a change in the air control vanes300-303, may indicate an occupant entered or exited the region.

Optionally or alternatively, a remote control unit 150-153 may be usedby an occupant to indicate that the region is occupied. For example, theremote control unit 150-153 may include a button that, when pressed,indicates the region is occupied. Furthermore, receiving any command,such as setting a desired temperature or a set-back time, issued withina region may be used to infer that the region is occupied. Absence ofany indication of occupancy for several minutes may indicate a region isnot occupied.

Artificial light can be differentiated from sunlight by the relativelylow level of illumination provided by artificial lights and by the rapidincrease or decrease in light level when a lamp is switched on or off,compared to the gradual increase or decrease in light level duringsunrise or sunset, moon rise or moon set. Thus, daytime versus nighttimemay be automatically distinguished, even if the clock 626 is not set.Even without the clock 626 being set, the register controllers 133-146may share their information about the detection of bright light and,thus, measure the number of daylight hours.

If the system clock 626 has been set, the controller 613 can determinethe times of sunrise and sunset by noting times when strong light beginsto shine on the photovoltaic cells 206 and when this strong light ceasesto shine on the photovoltaic cells 206. Thus, an arbitrary time zone maybe created, in which noon is made to correspond to the brightest averagelight level detected, or alternatively half way between sunrise andsunset, during a series of 24-hour periods.

The thermal infrared sensor 212 may also be used to measure an amount ofambient thermal infrared radiation in the region. Ambient thermalinfrared level is an important component of comfort level. By measuringboth air temperature and thermal infrared level, the network canmaintain a better comfort level. For example, the controlled registers113-120 may provide less heated air in areas with significant amounts ofthermal infrared radiation, such as from windows, thus achieving energysavings.

Power Supply

As noted, the photovoltaic cells 206 provide electric power for theregister controller. Optionally or alternatively, a fan (not shown)located in the air flow stream may be used to drive a generator (notshown). The fan should be positioned so it is never occluded by theadjustable damper or such that it is occluded only near the extremeclosed state of the damper. Optionally, a primary battery (not shown)and/or an external power supply (not shown) may be used.

FIG. 7 is a schematic circuit diagram of an exemplary power supply 600.Energy is supplied by photovoltaic cells V1-Vn 206 and/or a fan-poweredgenerator. An optional DC power input may also be provided, so that anexternal source may also be used. Diodes D1 and D2 combine the powerfrom the external source and the photovoltaic cells (and/or thefan-powered generator) into capacitor C1. Resistors R1 and R2 divide thevoltage from the external source to a level tolerable to amicroprocessor U4 to allow the two sources to be distinguished. Thevoltage on C1 is applied to a switching power converter U1. Thisconverter supplies a current output, which is supplied to rechargeablebatteries B1-Bn. The current supplied to the rechargeable batteriesB1-Bn is controlled, via a switching converter U1, by the microprocessorU4. The microprocessor U4 can also monitor the current in or out of therechargeable batteries B1-Bn via R3 and amplifier U2. The microprocessorU4 can thus maximize the current into the batteries, thus optimizingutilization of the power out of the solar cells for any light level.

Resistors R4 and R5 divide the voltage from the rechargeable batteriesB1-Bn to a level tolerated by the microprocessor U4. The microprocessorU4 is thus able to measure both voltage and current levels in therechargeable batteries B1-Bn to optimize battery charging.

Power from the rechargeable batteries B1-Bn is supplied directly to theservo motor and also to a switching power converter U3, which providesregulated voltage to the microprocessor U4 and other circuitry in theregister controller. Since the microprocessor U4 can ascertain therechargeable battery B1-Bn voltage, the microprocessor U4 can compensatemotor drive signals accordingly. The power converter U3 output isconnected to a large capacitor C2 that allows the microprocessor U4 toshut the converter U3 down much of the time, reducing energy used by theconverter U3. Other shutdown circuitry (not shown) allows themicroprocessor U4 to save additional power by turning devices on onlywhen they are needed. The circuitry is also designed so thatrechargeable battery B1-Bn charging occurs automatically, even if therechargeable battery B1-Bn voltage is too low for microprocessor U4operation.

Network

The goals of the network include conserving energy and enhancingcomfort. The network accomplishes these goals in a number of ways, someof which are summarized in Table 1.

TABLE 1 Network Goals Maintains desired temperature in all areas (bycontrolling the amount of conditioned air supplied to each region)Measures temperature more accurately and accounts for IR backgroundEliminates or reduces the overheating or cooling of any area of the homeSimplifies owner initiated temperature setback of selected areasSimplifies reducing heating/cooling of entire house at selected timesEnables setback when a room is unoccupied Reduces waste fromover-pressure in the ducts Prompts for or causes the circulation of airfrom overheated (over-cooled) areas to under heated (under-cooled) areaswith HVAC system blower alone Alarms for energy waste from open doors orwindows Identifies areas that need improved insulation or reducedinfiltration Measures overall system efficiency thereby improvingupgrade decisions

Although the register controllers 113-146 have been described as havingan RF transceiver for communicating with other nodes of the network,other forms of wireless communication, such as ultrasonic or infrared,may be used. Each network node has a unique communications addressassigned during manufacture and used for point-to-point communication.This address may also be used as the node's serial number. All nodesalso have a common (broadcast) address that all components respond to.

One use for the common address is to allow the handheld remote units150-153 to discover the unique address of any network node. This is doneby pointing the handheld remote unit 150-153 at a node and transmittinga command from the remote control unit 150-153 via the RF transceiver inthe remote control unit to all nodes, where the command causes the nodesto transmit their unique addresses via their infrared transceivers 606(FIG. 6). The remote control unit has an infrared transceiver 816 (FIG.8) that is directional and only receives this optical signal from thenode that the remote control unit 150-153 is pointed at. Once the remotecontrol unit has received a node's unique address, it can communicatewith that node explicitly over the normal RF wireless network. Theoptical path can be used to determine that the user of the remotecontrol unit is still pointing at the same component for all subsequentcommunications, but in this case a single flash of light from only thenode addressed by the remote control unit is sufficient to confirm thatthe correct node has been addressed. If the remote control unit fails todetect this flash, it will reinitiate the address discovery procedure.

The remote control unit allows the user to select a network component bypointing the remote at it like a gun, but avoids the expense of aseparate full duplex high speed optical communications system for eachcontrolled register. The proposed system requires the addition of only asingle LED, which can be used for other functions, such as to indicateto the owner that the controlled register is working properly. While theremote control unit must have a light detector, it needs to support onlylow speed communications that can be run by the microprocessor, withoutthe need for other dedicated hardware.

In some embodiments, a node returns its unique address over the lightpath. In other embodiments, other systems may be used. For example,because the remote control unit 150-153 normally has a list of alladdresses in the system 100, it may sequentially command each of them toflash its (visible or IR) LED until the remote control unit detects aflash. At installation, if the remote control unit has not alreadyacquired the list of unique component addresses, it may use thebroadcast address to discover all nodes in range, not all of which maybe in the local system 100. Nevertheless, use of optical feedback fromthe node allows a “point to select” mode to be used.

Each network node has several states, and among these are: New (neverinstalled); Discovery (installed in an HVAC system, but stilldiscovering other components); and Installed. When a controlled register113-126 is installed on a duct, the controlled register 113-126eventually detects air flow that is either hotter or colder than theambient temperature in the region. The register controller notes the(relative) time (UT) that air flow starts and stops. The existence ofhot or cold air passing through the register indicates that thecontrolled register has been installed in an HVAC system. At that time,the controlled register switches to discovery mode. The registercontroller sends out a request to the common address for all unitswithin communication range to respond with their unique addresses. Thisrequest is accompanied by the newly installed register controller's ownunique address. Alternatively the new unit may monitor all of thefrequencies used by networks of registers, and if appropriate, attach arequest to join at the end of the normal network transmission. In eithercase the unit only joins networks that appear to be on the same HVACsystem. As noted, this may be accomplished by comparing the times thatboth nodes observed recent starts and stops of air flow. If these timesare approximately equal, such as within about three seconds, the newlyinstalled node joins the communications network of the discovered node,and the newly installed node changes its mode to “installed.”

The network includes all the nodes that have set their states toindicate they are in the same network. The network may have anIdentification Number that is arbitrary but unique. One way to guaranteeuniqueness of the network ID is to use the unique address of any unit inthe network, for example the first register controller in the network.This node is elsewhere called the “oldest” component and is the basisfor network time, in that NT is identical to this node's UT.

A node may be removed from the network's list of nodes for any ofseveral reasons. For example, if a node has not communicated with anynode of the network for a substantial period of time, such as about aday, the network may mark the uncommunicative node as no longer a memberof the network. This might happen if a register has been removed fromthe HVAC system. If any node of the network identifies itself as amember of another network, it is removed as a member of this network. Ifa register controller records the HVAC system's on and off times assubstantially different from the consensus on-off times, the registercontroller is removed from the network.

If for any reason the “oldest” node is no longer a component of thenetwork, it is possible that it will become the “oldest” component of adifferent network. To maintain uniqueness, the network changes its ID tothe unique address of a different component, such as the numericallysmallest ID among the remaining nodes. The offset for NT need not bechanged, so that time may remain consistent within the network.

A controlled register 113-126 may also assume it has been installed whenit detects a threshold level of air flow. Requiring detection of hot orcold air and an air flow may reduce false attempts to install. However,because false attempts to install do little harm, it is possible toattempt to install on air flow only. A controlled register 113-126should not attempt to install itself until it has received a fairly fullpower supply charge and has detected a full system blower cycle ofminimum duration (for example greater than one minute), so it candetermine if it is in the same system as other units it discovers.

There are several methods of determining if two nodes are in the samesystem 100, but they all amount to discovering similarities in theirrespective environments. “Turn on” and “turn off” times for the air floware good indicators for controlled registers 113-126. To identify anetwork thermostat 160-163, temperature fluctuations over time may becorrelated, which should correlate best with a nearby controlledregister 113-126. Once that register controller is identified, all othersystem nodes may be revealed by that register controller. In the case ofa network thermostat 160-163, there may be a minimum correlation oftemperature over time and a minimum signal strength for thecommunication link before the network thermostat is incorporated intothe system 100. This acceptance threshold may be reduced over time, sothe network thermostat 160-163 is eventually accepted, even if thecorrelation and the signal are weak. It may be assumed that the networkthermostat 160-163 should be a part of some system and that a user wouldnot put a network thermostat in a region with no controlled registers.

As an additional protection against installation mistakes, in oneembodiment, register controllers 133-146 accept set point changes onlyfrom one network thermostat 160-163, and that network thermostat must bethe one with the highest correlation of temperature fluctuations withthe register controller. In addition, every change of set point may thenbe used to conduct an experiment to ensure that all register controllersare responding to the correct network thermostat, not a networkthermostat in a nearby region.

For example, if the system is heating, and the local set point isreduced below the current region temperature (such as by a humanadjusting the thermostat), all associated controlled registers may closetheir baffles to reduce air flow. This should result in a reduction intemperature, primarily in the region in which the network thermostat andits associated controlled register(s) are located. If there is a greatercorrelation with a different network thermostat or with a controlledregister that is not associated with this network thermostat, theassociation may be incorrect and should be changed.

The “experiment” described above was initiated as a result of an actionby a human. It is also possible for any node to initiate a similarexperiment, absent action by a human. For example, if the temperatureover time correlation is below a threshold, and there is a comparablecorrelation with other non-associated nodes, the node may automaticallyinitiate the experiment.

Just as an automatically configuring network should be prepared to addnew nodes, the network should also remove components that appear to haveleft the network. It is possible that a node has been removed by theowner to use on a different HVAC control system 100 that is withincommunication range. For example, the node may have been moved toanother zone in the same building. Continuing to treat this component asa member of the old network could cause malfunction or suboptimalperformance of the network. The HVAC control system 100 shouldperiodically or occasionally compare HVAC on and off times and checkother criteria, such as correlated temperature over time, to ensure thatmoved components are removed from the network.

A controlled register 113-126 can determine if it is sharing a regionwith another controlled register 113-126 by closing its damper and thenmonitoring the network to see if any other controlled register has hadto open its damper to compensate. The experiment may also be run byopening the damper and seeing which controlled registers had to closeits damper to compensate. Normally, the most effective technique(opening or closing) is the one that causes the greatest change in totalair flow into or out of the region. In addition, duct pressure at thecontrolled register that initiated the experiment and all otherregisters can be measured and compared. Closing a supply register shouldincrease the duct pressure at nearby supply registers, and opening asupply register should decrease the nearby supply register pressures.The results of these experiments can be combined with correlations oftemperature and duct pressure.

Return Register

In conventional HVAC systems, the air flow is controlled only by airsupply registers. The air return registers have no control baffle. In aconventional system, any attempt to control the air return registerswould make balancing the system difficult.

In some embodiments of the present invention, a controllable air returnregister is used improve the system's ability to move air from areasthat are too hot to where it is needed (or in the case of airconditioning, to move too cool air to where it is needed). With nocontrol of the air returns, return air would come from all areas andtends to be the average air temperature in the building. This wouldlimit the utility of simply moving air, without operating theheating/cooling device 103, to achieve comfort. In fact, if the systemattempts to move the air from all over a building to a specific region,a greater portion of the returned air comes from that region, becausethe region with the open supply register tends to have a higher airpressure than other regions with closed supply registers. Consequently,little or no net change is made, and energy is wasted operating theblower 106.

In the case of heating, having controlled baffles on all of the returnsallows the system to selectively move air from the hottest area to thecoldest area. A secondary use for the controlled air return is to limitair movement from the rest of the building to regions that have been setback or turned off.

Although the controlled return registers 123-126 have hardware similarto the controlled supply registers 113-120, the control algorithm may bedifferent. In some embodiments, the controlled return registers 123-126have only two damper positions: open and closed.

The highest priority for a return register is to ensure it never failsin the closed state. Because most of the time the network controlstemperature by adjusting the air supply registers, it is important thatan inoperative controlled return register does not interfere with thisprocess. To this end, the hardware should include a “default to open.”

Remote Control Unit

The main function of the remote control units 150-153 is to allow a userto communicate with the network, such as to set a desired temperaturewithin in specific region or to turn on or to turn off the supply ofconditioned air to the region. However, the remote control units 150-153do not act as central controls for the HVAC system. As noted, control ofthe HVAC system is distributed among at least the register controllers133-146.

Each remote control unit 150-153 enables the user to: set a desiredtemperature within a specific region; program a temperature set-backschedule for each region; program set-backs based on other conditions,such as room occupancy; set the time and date in the network; turn theHVAC system on or off, in toto or in a selected region; overrideautomatic installation parameters; display status information; displaysystem performance data; display suggestions from the network for energyconservation or comfort improvement; and display error messages, such asmessages related to dysfunctional components or inefficiencies.

FIG. 8 is a schematic block diagram of an exemplary remote control unit.A processor 800 executes instructions stored in a memory 803. Accordingto the instructions, the processor accepts user inputs via a set of userinterface buttons 806 and/or a touchscreen 819 and displays informationon a display 810 or the touchscreen 819. The processor 800 communicateswith a controller 613 (FIG. 6) in a nearby controlled register 113-120via an infrared transceiver 813 and/or an RF transceiver 816. Thus, theuser may use any remote control unit 150-153 to communicate with anycontrolled register 113-120 by aiming the infrared transceiver 813 atthe infrared transceiver 606 (FIG. 6) of the controlled register113-120.

Thermostat

Returning to FIG. 1, up to three types of thermostats may be used. Theoriginal HVAC system thermostat 108 may be retained to control theheating/cooling device 103 and blower 106. A network thermostat 163 thatis connected to control the heating/cooling device 103 and the blower106 may be connected to the original HVAC system thermostat 108, or thenetwork thermostat 163 may replace the HVAC system thermostat 108. Ineither case, the network thermostat 163 includes a wireless transceiver,so it can communicate with other nodes of the network. A user may set adesired temperature, such as with conventional user interface buttonsand a display on the network thermostat 163. The network thermostat 163sends information about the user inputs, such as a desired temperatureor set-back time, to the nodes of the network.

The third type of thermostat is a network thermostat 160 that is notconnected to control the HVAC system. In other respects, the networkthermostat 160 is similar to the network thermostat 163.

Network thermostats 160-163 may be added to any region. To easeinstallation, in some embodiments, network thermostats need no powerconnections. Each network thermostat 160-163 may have a photovoltaiccell on its front surface. The network thermostat may also haveprovision for a primary battery. While the network thermostat may havethe same temperature measuring devices (thermistor and/or IR) as theregister controllers, this is used primarily to determine whichcontrolled registers are in the same region as the thermostat. Onceinstalled in the network, the network thermostat may be completelyturned off until the user pushes a button. In this case, the power totransmit the new setting to the network may be generated as the buttonis pressed, such as in a manner similar to that used for remote lightingcontrols. The thermostat may be thin enough to look like an electricalswitch plate when it is glued to a wall.

As noted, a network thermostat 163 can replace the HVAC thermostat 108.To make the replacement of an existing thermostat simple, the networkthermostat 163 allows for the connection to the wiring to be donearbitrarily. One embodiment of the network thermostat 163 has 7 inputterminals, which provide a connector for every possible lead from theHVAC control 109. Once connected to the HVAC control 109, the networkthermostat 163 measures voltage, resistance and/or impedances betweenpairs of connections. These pairs are either power supplies or windingson relays that control heating, cooling, and the blower. There are, atmost, 6+5+4+3+2+1=21 such pairs. The power inputs should be obvious fromthe voltage across a pair. Pairs with a fairly low resistance are likelythe windings of control relays in the HVAC control 109. The networkthermostat may then determine which relays control the heating, coolingand blower by applying the HVAC supplied power to one or more of therelay leads and determining what happens, i.e., whether air flow begins,whether the flowing air is heated or cooled, etc. This mechanism notonly makes the installation of the network thermostat easy, it alsoprevents user installation errors.

The network thermostat 160 is primarily a user interface allowing theuser to observe the real temperature and the set point temperature, toadjust the set point temperature and to turn off the heating (cooling)to a region. As noted, the network thermostat 160 has local temperaturemeasuring capability, but that is just reported to the network and doesnot directly adjust any register. For this reason, the networkthermostat 160 only needs to be powered up for installation or after abutton is pushed. A combination of a primary battery and power generatedfrom pushing the button should allow a thermostat to install itself in anetwork and continue to perform its most important functions after thebattery dies.

Temperature Control Algorithm

Each intelligent register controller 133-140 in a controlled supplyregister 113-120, and optionally each intelligent register controller143-146 in a controlled return register 123-126, executes an algorithmthat determines how and when the respective register's adjustable dampershould be operated. In a system with generous power reserves available,the control algorithm can be quite simple, as illustrated by theflowchart of FIG. 9 For example, in heating mode, at 920, each registercontroller 133-146 opens its vanes when heat is supplied by theheating/cooling device 103 and blower 106, and at 923, the registercontrollers 133-146 close the vanes when their respective regions reachthe desired temperatures. By closing the vanes most of the way inconventional, i.e., uncontrolled, registers 128 in the region containingthe HVAC thermostat 108, the region serviced by the uncontrolledregisters 128 heat more slowly than the regions supplied by thecontrolled registers 112-120. The heating device 103 shuts off when theHVAC thermostat 108 is satisfied. By that time, the regions supplied bythe controlled registers 113-120 should have reached their respectivetarget temperatures, and their respective register controllers 133-128should have closed their adjustable dampers.

At 900, if air flow is detected, control passes to 903, where the roomtemperature is measured. If the HVAC system is operating in a heatingmode, at 906 control passes to 910, otherwise control passes to 913. At910, if the room is hotter than the target temperature for the room,control passes to 923, at which the vanes of the register are closed anincremental amount, such as a predetermined number of steps of astepping motor. On the other hand, if at 910 the room is not hot enough,control passes to 920, where the register is opened an incrementalamount. After a delay 926 to allow the room temperature to change inresponse to the increased or decreased airflow resulting from theincremental opening 920 or incremental closing 923 of the register,control returns to 900. Thus, as long as air is flowing through theregister, the control loop repeated compares the room temperature to thedesired room temperature and incrementally opens or closes the register,as needed. Optionally (not shown), if the room temperature is within apredetermined range of the desired temperature (i.e., within a “deadband”), the register opening may be left as it was in a previousiteration of the loop. Optionally (not shown), if the level of charge inthe battery is below a predetermined threshold, the register opening maybe left as it was in a previous iteration of the loop to conservebattery power that would otherwise be consumed operating the servo.

Similarly, if the HVAC system is operating in a cooling mode, at 913 thecomparison between the current room temperature and the desired roomtemperature causes the register to be incrementally opened 930 orincrementally closed 933.

In another embodiment, the algorithm is more complex, as illustrated inthe flowchart of FIG. 10 The vanes do not necessarily move continuouslyin reaction to real-time conditions. Instead, the vanes move only a stepor two at a time in accordance with an algorithm that monitors systembehavior over time and predicts the minimum needed adjustments, based onthe energy requirements and physical characteristics of each regionmaking up the entire system. In other words, the network collects datarelated to how much of a temperature change is caused by a certainchange in openness of a register. For example, it may be experimentallydetermined that, for a given register, during a particular season of theyear, a 10% change in the amount the register is open typically causes a0.3° F. change in room temperature. Once this data has been collected,at 1026, the amount by which a register should be incrementally openedor closed may be calculated, based on the difference between the currentroom temperature and the desired room temperature. Then, at 1043, 1046,1050 or 1053, the register may be opened or closed by the calculatedincremental amount. Other aspects of the flowchart of FIG. 10 aresimilar to the flow chart of FIG. 9.

Each node of the network, or at least each register controller 133-140in a controlled register, maintains a table (a Device Information Table(DIT)) of data for each other node in the network, or at least eachregister controller 133-140. Data in this table is used to maintain thecommunications network and to support the control algorithm. Most ofthis data is periodically or occasionally updated, such as every twominutes. A description of DIT entries and other data relevant to thecontrol calculation is now provided.

Current Measured Temperature (Tpresent)—A best estimate of regiontemperature at the device. For a controlled register 113-126, the floortemperature is measured by a thermistor and the ceiling temperature ismeasured by a thermal IR detector, as previously discussed. The reportedtemperature is a weighted average from the two devices. Remote controlunits 150-153 and network thermostats 160-163 measure temperature withinternal thermistors.

Target Temperature (Ttarget)—A temperature the controlled register112-126 is attempting to achieve, if the device is in a constanttemperature mode. On the other hand, if a schedule is active for thedevice, this value is ignored, and the target temperature set by theschedule is used.

Vent Position (controlled registers 112-126)—A percentage that the ventsare currently open.

Heating Vent Gain (Fventgainh)—A factor used to determine theeffectiveness of opening a vent a given amount. For example, this may becalculated as a rate of change in temperature a region might experiencefor a 25° C. outside temperature with the heating device 103 operatingand all vents in the building open 50%.

Cooling Vent Gain (Fventgainc)—A factor used to determine theeffectiveness of opening a vent a given amount. For example, this may becalculated as the rate of change in temperature a region mightexperience for a 25° C. outside temperature with the cooler 103operating and all vents in the building open 50%.

Heating and Cooling Temperature Position Factor (Fposh andFposc)—Regions near the outside of a building generally require energyinputs that are different than the inputs required by inside regions.These factors account for that difference.

Outside/Inside Air Temperature Factor (Foutin)—A factor based on thepercentage of time that the heating/cooling device 103 has operated overthe last 24-hour period, which is proportional to the difference ininside and outside temperatures. Blower 106 operation and temperatureare both monitored to rule out “blower-only” time.

Daily Temperature Pattern (Fpattern)—A temperature profile over thecourse of a day typically follows pattern similar to previous days, andthe maximum temperature typically occurs at about the same time from dayto day. The algorithm may include a factor based on this pattern. Forexample, the algorithm may anticipate a need to provide more or lessheating or cooling in the immediate or near future, based on thishistorical data. For example, the historical data may show thatadditional heating will likely be required beginning at about 5:00 PM,at least in certain rooms, such as because the sun ceases to shine atabout that time on the part of the building where the rooms are located.Thus, the HVAC control system 100 may begin heating those rooms,beginning a little before 5:00 PM. Such anticipatory heating or coolingmay even out the load on the heating/cooling device 103 (FIG. 1), thusreducing the capacity of the heating cooling device 103 required to meetinstantaneous needs.

Power Available—A variable that gives an indication of the poweravailable to a device. This may be an indication of the level to whichthe battery is charged. Any suitable range, such as integers from 0 to10, may be used. For example, 0 and 1 may indicate the device does nothave adequate power available to adjust its vents.

Dawn and Dusk Times—Each device utilizes its sensors to establish anestimate of dawn and dust times using two techniques. The first recordsthe output of the photovoltaic cells to ascertain a pattern of sunriseand sunset, as described above. The second monitors the airflow patternto determine when the peak heating or cooling times occur. (It may beassumed that the peak heating occurs at midnight, and the peak coolingoccurs at noon.) Since each device has the data from all other devices,these numbers can be combined to make the best estimate of dawn anddusk. Because all devices execute the same algorithm and use the samedata, all the devices arrive at the same values. Dawn and dusk time areused to time-calibrate a standard temperature pattern, described above.

As noted, the HVAC control system 100 includes no central controller.Each register controller 133-146 accumulates data from all otherregister controllers 133-146 in the system 100, and then each registercontroller 133-146 calculates its next action, taking into account thecalculated actions of all of the other register controllers 133-146.These calculations occur periodically or occasionally, such as every twominutes during active airflow periods. The calculation results in adecision to open or close the vanes one or more steps or leave the vanesunchanged. The objective is to heat or cool all regions at the same rateof temperature change so, when the airflow ceases, each room will haveachieved its target temperature. In systems 100 that include at leasttwo intelligently controlled registers 113-126, barring any overridingtemperature programming from any remote control unit 150-153 or networkthermostat 160 or 163, i.e., absent an overt set point, the intelligentcontrolled registers 113-126 try to maintain the same temperature at allintelligent controlled registers 113-126. For example if the HVAC system103 is heating, the cooler intelligent controlled registers 113-126 willincrease their airflows. If the coolest intelligent controlled register113-126 is all of the way open, warmer intelligent controlled registers113-126 will decrease their airflows. If all the intelligent controlledregisters 113-126 are in the network 100, all areas will reach the sametemperature, and that temperature must be the temperature set by theHVAC systems thermostat 108. The decision to open or close anintelligent controlled register's 113-126 damper is made by thatregister. The basis for this decision comes from the information theintelligent controlled register 113-126 has received and saved from allother network components, as well as the register's own status andhistory. The algorithm proceeds as follows, as illustrated by theflowchart in FIG. 10. Heating or cooling versions of the factors arechosen to match the current mode of the system.

At 1020, for each controlled register 113-126, determine a target changein temperature to be achieved over the current airflow cycle. If aset-back, vacation or other schedule is active for the register, thetarget temperature is used from that source.

At 1023, for each controlled register 113-126, calculate a valueproportional to the energy flow, such as according to equation (1).

Energy flowcontribution(n)=(Ttarget−Tpresent)*Fventgain*Fpos*Foutin*Fpattern  (1)

At 1026, sum and normalize the values just calculated to determine thetarget vent openings required throughout the system 100. Compensate forany registers that may be stuck in position due to inadequate powerreserves. Preferably, adjust the values so that at least one controlledsupply register 113-120 will have it vents fully opened. This maximizesair flow and minimizes air leakage.

At 1030, from these results, determine the direction and rates theregister vanes should be moved. Examine the time at which a movementlast occurred to assess if a new movement is due. If so, execute thatmovement. As noted, if the current room temperature is within the deadband, or if the register's battery charge level is low, the registervanes may be left unchanged, at least for the current iteration throughthe control loop.

When air flow ceases, update the calculated values for each of thefactors listed above, based on data from the air flow cycle.

Air Movement

Moving air from one region to another region, without operating theheating/cooling device 103, can save energy while increasing comfort, ifseveral criteria are met. First, there should be a temperaturedifference between the two regions. Second, there should be at least tworegions that are within their “dead bands,” i.e., temperatures that arewithin a predetermined range, such as about three degrees, of their setpoints. However, at least one of the regions should be above its targettemperature, and at least one of the regions should be below its targettemperature. In addition, the region above its target temperature shouldbe hotter than the region that is below its target temperature.

Each register controller 113-146 may have several goals, including:maintaining a desired temperature, minimizing energy consumption by theHVAC system and maintaining a minimum energy level in its power supply.If a minimum charge is maintained in its power supply, a registercontroller attempts to maintain the desired temperature range, and thento minimize energy consumption by the HVAC system.

If a register controller 113-146 is low on power, it reduces its powerconsumption by first increasing its dead band. If the power reservecontinues to decline, at a predetermined point the register controllernotifies the network of the problem and turns itself off. The registercontroller does not turn on again until a minimum power level (higherthan the turn-off level) has been restored.

The main way an owner can help the system minimize HVAC energyconsumption is to expand the dead band. The network has a dead band oftemperatures in which an area is assumed to be comfortable. If thesystem is heating, and a controlled register is in a region that isbelow the dead band temperature range, the controlled register normallyopens its damper until the region reaches minimum desired temperature.If the controlled register receives information over the networkindicating that other regions failed to reach their desiredtemperatures, the controlled register temporarily expands its dead band,thereby permitting the temperature of its region to be lower or higher(depending on whether the HVAC system is heating or cooling) than theoriginal set point. Intelligent controlled registers 113-126 have one oftwo types of set points: assumed or overt. An overt set point is atemperature target sent to a set of intelligent controlled registers113-126 from the remote control unit 150-153 or from a networkthermostat 160. Intelligent controlled registers 113-126 with overt setpoints attempt to maintain that temperature. On the other hand, anassumed set point is a temperature the intelligent controlled register113-126 calculates on its own, such that all rooms fed by intelligentcontrolled registers 113-126 with assumed set points will be at a sametemperature. Intelligent controlled registers 113-126 with assumed setpoints attempt to come to a common temperature. Once at least twointelligent controlled registers 113-126 are in a network, barring anoverriding temperature programming from a remote source, such as aremote control unit 150-153, network thermostat 163, etc., i.e., theintelligent controlled registers 113-126 have assumed set points, theintelligent controlled registers 113-126 try to maintain equaltemperatures at all the intelligent controlled registers 113-126. Thus,if heating and one intelligent controlled register 113-126 with anassumed set point reaches a temperature, cooler intelligent controlledregisters 113-126 raise their assumed set points to match the achievedtemperature. If the room/region with the HVAC thermostat 108 is fed byan intelligent controlled register 113-126 that has an assumed setpoint, the HVAC system 103 will not shut off until the room reaches theHVAC thermostat 108 set point, regardless of the assumed set point.However, until all the intelligent controlled registers 113-126 withassumed set points achieve the common temperature, warmer (assumingheating) registers, including the one in the room with the HVACthermostat 108, will reduce their airflows, to the benefit of coolerregisters. Therefore, logically, the HVAC thermostat 108 will not besatisfied until all intelligent controlled registers 113-126 withassumed set points have achieved a temperature equal to the HVACthermostat 108 set point. Of course, once the HVAC system thermostat 108is satisfied, it shuts off the HVAC system 103, but by that time, allrooms fed by intelligent controlled registers 113-126 with assumed setpoints have reached the temperature set on the HVAC thermostat 108. Forexample, if the HVAC system is heating, and the coolest controlledregister is fully open but has failed to reach its minimum desiredtemperature, warmer controlled registers decrease their respectiveairflows, thereby making more air pressure and air flow available forthe coolest controlled register. The goal of minimizing HVAC energyconsumption causes the controlled register to close its damper by anamount that is a function of how far from the comfortable temperaturethe room air is, and how long it has been that way. If all of theregisters in a system are in the same network, these registeradjustments result in all regions coming to the same temperature, atemperature set by the HVAC system thermostat 108. This forms a basisfor automatic network self-installation, without a need to connect tothe HVAC system or replace and existing HVAC system thermostat.Attempting to balance the temperatures by first opening the coolestregion's register (if the HVAC system is heating, or opening the warmestregion's register if the HVAC system is cooling) ensures that allregisters are as open as possible and still achieves a balance. This, inturn, ensures that the HVAC system has the least pressure in its ducts,thus minimizing energy waste in the HVAC blower and from duct leakage.

FIG. 11 is a flowchart illustrating operation of an intelligentcontrolled register 113-120. At 1100, air temperature of a region ismeasured. At 1103, optionally, a signal is received from a remotecontrol unit. The signal may convey information about a desired setpoint temperature, set-back time, or the like. At 1106, signals arereceived from one or more first other intelligent controlled registers113-120. The signals may convey information about measured airtemperatures, desired set point temperatures, battery charge levels, airflow rates, damper states, and the like for the respective intelligentcontrolled register(s). At 1110, the information received from the otherintelligent controlled register(s), along with corresponding informationabout this intelligent controlled register, is sent (“forwarded”), sothat other intelligent controlled registers that are not within wirelesscommunication range of the first other intelligent controlled registersmay receive the information. That is, the information is distributed toother nodes of the network. At 1113, a desired damper operation iscalculated, based at least in part on the available information aboutthis and the other intelligent controlled registers of the network. Thecalculation may also involve information received from the remotecontrol unit and/or a wireless thermostat. At 1116, a servo is driven tooperate a damper, according to the calculated desired damper operation.Control then returns to 1100.

Network Communication

In normal operation, the devices in the HVAC control system 100 may beasleep between messages, and the amount of time that receivers are on isminimized. This is done to conserve the small amount of power (typicallysupplied by solar cells) that is available to each device. All of thedevices in the network wake up in synchronization very briefly, such asat regular intervals, such as every two seconds, to see if a remotecontrol is attempting to communicate. During one of these wake-upperiods, at another interval, such as every two minutes, each of thedevices in the system 100 passes a standard data messages in successionto all of the other devices. The standard data message may includecurrent status and critical data for the device and additionalinformation that is designed to optimize and maintain the integrity ofthe network. Each message contains an embedded device ID and a CRCmessage integrity check.

Each device maintains a Device Information Table (DIT). This tablecontains detailed information about all of the devices in the network.The DIT may be updated over the course of several message bursts. Thedata includes power stability and availability information for eachdevice, as well as data on the reliability of reception of each deviceby the other devices. This allows a device to request forwardingchannels to be set up, so that it may acquire data from devices itcannot directly receive from reliably.

Since all devices have data available from all other devices, and alldevices run the same software, each individual device is able to computethe control decisions for the entire network and then locally apply thedecisions that are applicable to itself. This is the key design elementthat allows the system 100 to operate without a central controller.

Exemplary numbers are given for the various timings of the system. Manyof these values are defined by system settings in the software and aresubject to change. The values given here are only exemplary; othervalues may be used, based on needs of the system, user preferences andother design considerations.

Typically, after the system 100 has formed a working network, periodicor occasional communication burst are used. In one embodiment, every twominutes, all of the devices in the system 100 pass data betweenthemselves in a burst of successive messages, as illustrated in FIG. 12.Portions of the message burst of FIG. 12 are now described.

IDQ—During this 10 mSec. time slot, each device calibrates an internalsynthesizer, enables its receiver, and listens for an ID query commandfrom the remote. The IDQ search occurs every 2 seconds. The remainder ofthe burst occurs only at the two-minute interval.

Dev 0—Dev n—This is the normal succession of transmissions by eachmember of the network. They start at predetermined times in 2 mSec.increments. If a device fails to transmit, the next device will stilltransmit at its allotted time. The first device transmits its data twiceas part of the collision avoidance system, which is described below.

FWD—One or more packets may appear in this position for forwarded data.A forwarded data packet is identical to that originally sent by thedevice being forwarded. Forwarding is explained later in this document.

JOIN—New devices requesting membership in the network transmit a packetduring this time. Joining the network follows a protocol described laterin this document.

UPDT—A long block with software update data may be appended to themessage stream at this position. Devices will only look for this blockif the software update bit in the status byte of the previously receivedpacket is set.

IRID—If the remote queried to identify a device during the IDQ period,all devices will respond with an ID message using the infrared (IR)link. If the remote query occurs at the time a message burst isscheduled, the IR response occurs at the end of the message burst asshown. Otherwise, the IR response occurs immediately after the query.

Devices in the system have very limited power available to them. When anew device is installed, it may have some power stored in rechargeablebattery, or the battery might need to be charged before thenewly-installed device can become a reliable member of the system 100.When a device “wakes up” for the first time, it assesses the powerreserves available to it. It will not attempt to join or start acommunications network until it determines that it has adequate powerreserves to support reliable communication for twenty-four hours.Operations performed by a device upon waking, such as searching for anetwork to join, are illustrated in a flowchart in FIGS. 13A and 13B.

A device can stop functioning if it suffers a loss of power for a longextended period. As a result, it would have stopped communicating in anetwork it was previously part of while the device was out ofcommission, a number of events might have occurred. In most cases, thenetwork would have resumed normal operation without the dropped member.RF interference may have caused the network to shift to an alternatefrequency. Discovery of another network operating at the same frequencymay have caused the network to change to another frequency. The devicemay have been taken out of the network and placed into another. Alldevices in the network may have dropped out. The device may be new andnever have been part of a network before.

Once reliable power has been established, the device checks non-volatilememory to see if it was previously part of a network. If it was part ofa network, it will look in non-volatile memory for the position it heldin the message burst sequence and for the selected communicationfrequency and network ID.

In all cases, the device will then wait until its internal airflowsensor indicates that the HVAC fan has been activated. Once it seesairflow, it records the time at which the airflow started and enablesits receiver. If it was previously part of a network, it will listenfirst at the memorized frequency. Otherwise, it will listen at thedefault frequency. It will listen at the starting frequency for 2.5minutes. If a network is not found, it will shift to the nextalternative frequency and make the same search. It will step through allof the frequencies twice in this manner. As it steps through thefrequencies, the device will make a record of those frequencies thatwere clear of interference or other networks.

The receiver consumes significant power and, in most cases, cannot berun continuously. If the search for a network is unsuccessful, thereceiver will be shut down and the search will be tried again at a latertime determined by the available power.

If a network is found with the same airflow time, the search ends. Aformer member that has not lost its time slot merely resumestransmission. A new device or a former network member that has lost itstime slot will enter the network joining process described below. Adevice that was part of a network previously but finds a differentnetwork ID may have been removed from one network and placed in another,but there is a small chance that it has discovered another network andthat the furnaces came on at the same time. This case is handled byactions of the self-repair process described later in this document.

If a network is found with a different airflow start time, that networkwill be ignored and the search will resume when the channel is againclear.

If no network is found, a new device will attempt to establish one. Todo this, it will restart its receiver at the lowest frequency that ithas found to be clear of interference or other network traffic. It willthen search at this frequency for a pseudo-random amount of time rangingform zero to 2.5 minutes. If no other device is found in that time, itwill attempt to form a new network, as described in the followingsection.

The above discussion assumes that device has access to an airflowsensor, as do registers, main thermostats, and remotes docked to athermostat back. Room thermostats and freestanding remotes do not havedirect access to airflow sensors. These devices monitor temperaturesover a length of time to correlate with changes in room temperature andthus calculate an equivalent airflow start time. If a remote is used toaccess a device that is connected to a network, it will obtain thenetwork information from the device and join at that time.

The process of network formation is illustrated by a flowchart in FIG.14. The process is typically initiated by a register. All practicalsystems contain at least one register, and registers will also have thenecessary access to airflow sensors.

To form the network, the device transmits the MSG0a, MSG0b sequencedescribed above, looking for the presence of a carrier after eachmessage. If no carrier is found, it assumes it is the first messenger onthe network, and continues to transmit accordingly. Other devices willform around it according to the network joining process described below.If a carrier is found immediately after either MSG0a or MSG0b, it isassumed that another device is trying to send in the MSG0 position, andthe device restarts the process of looking for an established network.The chances of such a collision are extremely small. The transmitterwill only start if it sees a clear channel. The chance of twotransmitters starting at the same time is about 5 μSec./2 minutes or onein 4.17E-8. The device established as the first messenger drops off thenetwork and restarts the process if no other devices attempt to joinwithin 24 hours.

A device that desires to join the network typically first finds anexisting network using the procedure detailed above and illustrated by aflowchart in FIG. 15.

It then sends a standard data message twice. The first is during the“join” time slot interval described above. The second is at time withinthe span of time that would be required for a message burst for amaximum sized system. The time slot at which the device sends itsmessage is determined by a pseudo-random number.

When the device that is the first messenger sees a message in the “join”time slot, it keeps its listening open for the remainder of the maximumsized message burst. If it sees one or more valid messages during thattime it will, on the next burst, send Ids for the new devices seen inthe cyclic data areas of MSG0a and MSG0b. It will also tell thesedevices their position in the message burst. After that point the newdevices will begin to transmit in their allotted time slots. Thisprocess continues until all requesting devices have joined the network.Some collisions may occur during this time, but the devices will all bejoined over a few cycles.

Each network member collects data from all of the other members. Theremay be physical problems, such as excessive distance or pathobstructions, that prevent direct reception of a message from one memberto another. To overcome this difficulty, a message forwarding system isimplemented that operates as follows:

1—The data packet transmitted by each member contains three values thatassist in the establishment of a forwarding link. These are the ID ofthe previous member and a rotating triplet consisting of the ID, receivesignal strength, and power reliability index of each of the othermembers in the network.

2—Each member builds a Device Information Table (DIT) that contains adata block for each other network member consisting of ID, powerreliability index, and receive signal strengths for all other members inthe network.

3—The member that lacks data from another member analyzes the table todetermine the best member to select as a forwarder for the missing data.Selection is based on the reliability of power and received signalquality from both the missing member and the requesting member. Therequesting device then sends a request to the selected forwarder toregularly forward the missing data. This request is contained in thecyclic data section of the requesting member's standard data message.

The remote control 150-153 can be used in a variety of modes. In mostsystems, it is used to enter user preferences, such as temperaturetargets and schedules, into the system. To do this, the remote may bepointed at a device to send an RF query message to it and receives an IRresponse from it. This is called point-to-connect mode. The remote canalso interact with devices remotely via RF, serving as an “armchairconsole” for the system. It can also be docked with a thermostat to actas the central furnace-controlling thermostat for the system.

When docked with a thermostat, the remote usually can receive power fromthe thermostat circuit. In this case, it connects to the system likeother devices and communicates at the regular two-minute interval.

If not docked, the remote can operate in the same regular communicationmode or, to conserve power and extend battery life, it can communicateat much longer intervals, dropping off the network and rejoining it asneeded.

When operated in point-to-connect mode, the remote can access the devicequickly in the following manner:

Point to Connect Device Acquisition—When the remote is commanded toconnect to a device using the infrared (IR) link, the process is asfollows:

1—If the remote has been actively communicating with the network, itwill time the sending of the query message so as not to interfere. Ifnot, it checks to see if RF traffic is present. If so, the remote willwait until the traffic stops, monitoring the message burst so that itwill be synchronized to further traffic. It then sends an RF ID querymessage.

2—The remote waits for an immediate IR response if no RF traffic waspresent, or for a response at the end of the traffic. If a response isreceived, the remote proceeds with processing. If not, the remoterepeats the enquiry until a response is received, or 2.5 seconds haselapsed. After each enquiry, the remote checks for RF traffic. Iftraffic is found, the remote records the time of the traffic andpredicts the time of the next loop so that it can avoid futureinterference with the network. The IR message returned also includes thetime of the next RF loop for the same purpose. The message also includesthe device ID and, if established, network ID.

3—The responding device will now have “awakened” so that it continuouslylooks for additional addressed RF enquiries from the remote. Theseinclude requests to send data or settings information and downloads fromthe remote of updated information.

4—Once the remote has received the settings information from the device,it will use the variables table and main display screen corresponding tothat device.

5—If a timeout period of no activity occurs, the device will return tonormal operation.

Whenever the remote is on, it monitors the network, updating informationfrom all other devices. A future remote screen will allow examination ofthe general health of the network.

The network is designed to be self-healing. Changes to the structure ofthe network follow the same general model as the method of establishingforwarding paths. Each device in the network is expected to act as aconscientious member. It is responsible for its own welfare, being sureit has adequate power before attempting transmissions or other actions.If it cannot hear one of the other members, it will ask another memberto relay messages, but only after being sure the other member hasadequate power reserves to handle such requests, and that the othermember is also able to clearly hear the distant device. If a devicedetermines that it will soon drop off the network due to a loss of poweror other problem, it will inform the other members of the time when thedrop-out will occur.

Interference and Changing Frequency—It is possible that two networks canbe operating at the same frequency but not see each other because theyhave different start times. Eventually, as they drift due to slightdifferences in their crystal frequencies, they will collide. When thisoccurs, one or both networks will shift frequency.

Dropping a Device—A device will drop out if airflow times do not match(checked at time of second burst after airflow starts). Loss of powermay cause a device to drop out. If so, it will notify the network inadvance that it is about to leave.

Reassignment of Burst Position—Transmissions on the network aresynchronized to the first device to send a message during each burst.The device performing that task is effectively the first device to askfor it when the network is formed. That device will continue to performthe task unless it develops a reliability problem that causes it to dropfrom the network. In that case, it will inform the network that it isdropping out. Another device will assume the “first messenger” roleautomatically based on the data in the DIT.

When devices receive an information update message, if devices in thesystem are discovered not to contain the most current code revision, thelowest ID numbered device with the most current code revision willbroadcast a copy of the code. Those devices that are not current willupdate themselves,

Normally, message bursts occur every two minutes, as described above. Ademonstration mode can be entered via the remote. In this mode, themessage burst occurs every two seconds. Demonstration mode may causeother operation changes within devices that vary according to the devicetype.

The standard device data packet is 48 bytes long, and takes 1536 μSec.to transmit at 250 Kbps. The remainder of the 2 mSec. time slot allowsfor RX/TX turnaround. An exemplary data packet is illustrated in FIG.21.

Cyclic Data—Some data elements only need infrequent update. By nottransmitting these every cycle, the average packet length can bereduced, reducing reception time, and thus, power requirements. Thelargest of these is a firmware update, which is sent and accumulated insmall parcels that are stored in serial EEPROM by the receiving devicefor program update when the entire file is complete. Includes thefollowing:

Network ID

Reception quality from all other devices

Power stability indicator

Time of last airflow

Software rev

Time clocks—UT,

Device ID—Each product contains a unique 32-bit device ID or serialnumber that is programmed in at manufacture. The three MSBs of the IDalso indicates the type of device—0=register, 1=thermostat, 7=remote.

Error Checking—A 16-bit CRC is appended to all packets. Reception of amessage that fails its CRC check causes that message to be discarded.The data update frequency is great enough that an occasional discardedpacket causes no problems.

On query from the remote, the device sends settings information via adevice settings data packet, an example of which is shown schematicallyin FIG. 22.

Short packets are sent by the remote to cause all devices to send theirIDs via IR or other information via RF. These packets total 26 bytes inlength, requiring 704 μSec. to transmit. An example of such a remotecommand packet is shown schematically in FIG. 23.

The remote standard update packet is 48 bytes long and is used to updatestandard information in a device after it has been edited by the remote.An example of such a remote standard update packet is shownschematically in FIG. 24.

The remote settings update packets is 48 bytes long and is used toupdate settings information in a device after it has been edited by theremote. An example of such a remote settings update packet is shownschematically in FIG. 25.

Each device maintains a table that records the most recent datatransmitted by all devices in the system as well as some historicaldata. An example of such a device information table is shownschematically in FIG. 26.

Remote—The remote looks for the loop like any other device. An ID queryRF message is queued for transmission. If a no-carrier space is found,the remote will send repeated queries, waiting each time for an IRresponse. If an RF carrier is found, a response will be looked for afterthe end of the loop.

Device—If an IR ID message request is received during the firstinterval, the response will be deferred until after the end of thechain. If a response is received when there is no following chain, theresponse will be sent immediately.

Remote—the remote looks for the loop like any other device. Once itfinds the loop, it avoids direct communications during scheduled looptimes. Otherwise, it will send messages anytime there is no carrier. Ifthe remote transmits at the same time as the beginning of the loop, itwill cause interference for that one time, but the system is designed torecover. Successive loops will not be interfered with.

The MSP processors used in the system may contain twice the memoryneeded to support their programs. Code updates write into alternatehalves of the memory so that, if an update should fail, the device cancontinue to operate with the previous version of the code.

A unique motor may be implemented as part of the design of an HVACregister, according to an embodiment of the present invention. Theconstruction of one embodiment of such a motor is illustrated in FIGS.16 and 17. This motor meets the following objectives:

Low Cost—in both components and labor

Integrated Detent—to maintain position when power is removed

High Power Efficiency—to allow it to be driven from a source of minimalpower, such as an array of low-cost solar cells

According to one embodiment, the motor is a 4-phase stepper motor. Inthis implementation, two stator stacks are formed as illustrated in FIG.17, where the components of the left half of the motor have been shownin an exploded view. The first component to the right of the printedcircuit board (PCB) 1700 is the bottom pole ring 1703. This is followedby a coil of wire 1706 wound on an insulating bobbin and then the toppole ring 1710. These components form one of the stators. The nextcomponent to the right is a rotor ring magnet 1713, which has beenmagnetized with alternating poles around its circumference at the samepitch as the two pole rings 1703 and 1710. The final component is therotor housing 1716, to which the rotor magnet is permanently mounted. Asimilar second assembly 1720 mounts to the right to form a second statorand rotor. The two rotor housings include integrated gear features 1723and 1726 that cause symmetrical counter-rotation of the two rotors withan offset of one pole position between the rotors. This causes the motorto act as a 4-phase stepper as the coils are energized in theconventional manner.

The cost savings of this motor over other forms that might be utilizedare based on the following:

Stamped Pole Construction—The pole rings 1703 and 1710 are stamped formsheet metal material. This is an efficient and inexpensive manufacturingprocess.

Simple Coil—The coil 1706 design is the simplest of forms, reducingconstruction costs. Because the coil 1706 is mounted directly to the PCB1700, no cost is incurred in the attachment of the lead wires neededwith conventional motors.

Integration with PCB—The PCB 1700 is the mounting for the motor. Theback of the bobbin has integrated clips which eliminate assembly screws,and plated holes in the PCB form the outer half of the bearings for therotors.

Multiple use of Rotor Housings—The rotor housings are not only part ofthe motor, but form part of the position sensor described below, includethe arm for manual adjustment of the register, and mount directly to theregister vanes.

The pole segments of the motor are designed to cause deliberate detents.These are designed to hold the position of the vanes under airflowconditions even when power is removed from the motor.

High power efficiency is achieved partially through the absence ofmechanical loss components such as gears and couplers. The motor isdesigned to have a large diameter to achieve high toque without therequirement of reduction gearing. The high ratio the motor diameter tothe gap between the rotor and stator contributes to higher efficiency.The external rotor design allows for a relatively large coil size,reducing electrical resistance losses.

A sensor, illustrated in FIGS. 18 and 19, according to one embodiment ofthe present invention, is employed that is based on changes inelectrical capacitance. The design is very low in cost, making use ofthe PCB 1700 and the rotor housing 1716 of one on the sections of themotor described above. The sensor operates in the following manner.Radial electrically conductive pads 1800 are disposed on the PCB 1700around the center of a rotor hole 1803. Each of the radial pads 1800around the circumference of the center of the rotor hole 1803 issequentially electronically connected to a circuit that measurescapacitance to ground or some other reference node. This capacitance isaffected by the position of the rotor 1716, which is made of a metallicof metallically coated material. The body of the rotor is groundedthrough motor components. As the rotor rotates, one or more of theradial pads becomes partially or fully uncovered, changing capacitanceto ground. The position of the rotor can thus be calculated from themeasures capacitance values.

Application to Electrical Heating Systems

The HVAC control system 100 can be applied to heating systemsincorporating an electric boiler or electric resistance baseboardheaters. A system using an electric boiler is really a hydronic system,as described above.

FIG. 20 shows a typical home heating system using baseboard electricalresistance heaters. Multiple heating circuits are routed from a centralbreaker box through a load controller. Each circuit is then routed viaone or more electrical high-voltage thermostats to one or more baseboardheaters. Toroidal current transformers surround each of the main powerwires entering the breaker box, and sensing wires from thesetransformers enter the load controller box. An electronic assembly inthe load controller switches the heating circuits on and off to limitthe maximum instantaneous load current drawn. This is done to minimizeenergy expense.

An HVAC control system for an electric heating system has the samefeatures and advantages as an HVAC control system for a forced-airsystem, except for the redistribution of air. Combined systems can beimplemented utilizing forced-air, hydronic and/or electric elements asneeded.

An electric baseboard heating system using an HVAC control system asdescribed herein may replace the standard electric thermostats with anelectric thermostat. This device may utilize the control capabilities ofa controllable register (as described above), but may control a relay(s)or triac(s) to control electric current to the heating element. Sincethe electric thermostat may be wall mounted, it may also contain thedisplay and buttons of the standard wireless thermostat 160, describedabove with respect to FIG. 1. All elements of this system maycommunicate wirelessly (or optionally through wired connections) withother components, such as wall thermostats and remote controls in thesame manner as in a forced-air system. One other component, awhole-house current sensor transceiver, may be added in an electricheating control system. This device utilizes the current sensors alreadyconnected to the load controller and taps into the signals inside theload controller box. Installation of this system is not a “drop-in,” asdescribed above for a forced-air system. It requires the low-levelelectrical work of replacing the electrical thermostats and adding thewhole-house current sensor transceiver.

In accordance with an exemplary embodiment, systems and methods forcontrolling HVAC systems are provided. While specific values chosen forthese embodiments are recited, it is to be understood that, within thescope of the invention, the values of all of parameters may vary overwide ranges to suit different applications.

An intelligent register controller has been described as including aprocessor controlled by instructions stored in a memory. The memory maybe random access memory (RAM), read-only memory (ROM), flash memory orany other memory, or combination thereof, suitable for storing controlsoftware or other instructions and data. Some of the functions performedby the intelligent register controller have been described withreference to flowcharts and/or block diagrams. Those skilled in the artshould readily appreciate that functions, operations, decisions, etc. ofall or a portion of each block, or a combination of blocks, of theflowcharts or block diagrams may be implemented as computer programinstructions, software, hardware, firmware or combinations thereof.Those skilled in the art should also readily appreciate thatinstructions or programs defining the functions of the present inventionmay be delivered to a processor in many forms, including, but notlimited to, information permanently stored on non-writable storage media(e.g. read-only memory devices within a computer, such as ROM, ordevices readable by a computer I/O attachment, such as CD-ROM or DVDdisks), information alterably stored on writable storage media (e.g.floppy disks, removable flash memory and hard drives) or informationconveyed to a computer through communication media, including wired orwireless computer networks. In addition, while the invention may beembodied in software, the functions necessary to implement the inventionmay optionally or alternatively be embodied in part or in whole usingfirmware and/or hardware components, such as combinatorial logic,Application Specific Integrated Circuits (ASICs), Field-ProgrammableGate Arrays (FPGAs) or other hardware or some combination of hardware,software and/or firmware components.

While the invention is described through the above-described exemplaryembodiments, it will be understood by those of ordinary skill in the artthat modifications to, and variations of, the illustrated embodimentsmay be made without departing from the inventive concepts disclosedherein. For example, although some aspects of a system for controllingan HVAC system have been described with reference to a flowchart, thoseskilled in the art should readily appreciate that functions, operations,decisions, etc. of all or a portion of each block, or a combination ofblocks, of the flowchart may be combined, separated into separateoperations or performed in other orders. Moreover, while the embodimentsare described in connection with various illustrative data structures,one skilled in the art will recognize that the system may be embodiedusing a variety of data structures. Furthermore, disclosed aspects, orportions of these aspects, may be combined in ways not listed above.Accordingly, the invention should not be viewed as being limited to thedisclosed embodiment(s).

What is claimed is:
 1. A method for operating an intelligent controlledHVAC vent of a plurality of intelligent controlled HVAC vents, at leastone intelligent controlled HVAC vent of the plurality of intelligentcontrolled HVAC vents operating without an externally set temperaturegoal, the method comprising, at each intelligent controlled HVAC ventthat has no externally set temperature goal: measuring a temperature ofa location fed by the intelligent controlled HVAC vent; automaticallywirelessly coordinating among all intelligent controlled HVAC vents ofthe plurality of intelligent controlled HVAC vents that have noexternally set temperature goals, with an aim toward achieving equaltemperatures at all locations fed by the intelligent controlled HVACvents that have no externally set temperature goals; ascertaining anextent to which the intelligent controlled HVAC vent is open; wirelesslyreceiving first information indicating, respectively, an extent to whicheach other intelligent controlled HVAC vents is open; and automaticallyadjusting the extent to which the intelligent controlled HVAC vent isopen, such that when a comparable adjustment is made by all intelligentcontrolled HVAC vents of the plurality of intelligent controlled HVACvents, at least one intelligent controlled HVAC vents of the pluralityof intelligent controlled HVAC vents is fully open.
 2. A methodaccording to claim 1, further comprising: wirelessly receiving secondinformation indicating a respective temperature of a respective locationfed by each other intelligent controlled HVAC vent that has noexternally set temperature goal; and automatically recalculating theextent to which the intelligent controlled HVAC vent should be open,based on the temperatures of locations fed by intelligent controlledHVAC vents that have no externally set temperature goals.
 3. A methodaccording to claim 2, wherein automatically recalculating the extent towhich the intelligent controlled HVAC vent should be open comprises:comparing the temperature of the location fed by the intelligentcontrolled HVAC vent to the second information; and if a result of thecomparing indicates the temperature of the location fed by theintelligent controlled HVAC vent is less than a temperature of at leastone location fed by another intelligent controlled HVAC vent that has noexternally set temperature goal, automatically increasing airflowthrough the intelligent controlled HVAC vent.
 4. A method according toclaim 3, wherein automatically increasing the airflow comprises:ascertaining whether a damper of the location fed by the intelligentcontrolled HVAC vent is fully open; and if the damper is ascertained tobe not fully open, automatically fully opening the damper.
 5. A methodaccording to claim 2, wherein automatically recalculating the extent towhich the intelligent controlled HVAC vent should be open comprises:comparing the temperature of the location fed by the intelligentcontrolled HVAC vent to the second information; and if a result of thecomparing indicates the temperature of the location fed by theintelligent controlled HVAC vent is greater than a temperature of atleast one location fed by another intelligent controlled HVAC vent thathas no externally set temperature goal, automatically increasing airflowthrough the intelligent controlled HVAC vent.
 6. A method according toclaim 5, wherein automatically increasing the airflow comprises:ascertaining whether a damper of the location fed by the intelligentcontrolled HVAC vent is fully open; and if the damper is ascertained tobe not fully open, automatically fully opening the damper.
 7. A methodaccording to claim 2, wherein automatically recalculating the extent towhich the intelligent controlled HVAC vent should be open comprises:comparing the temperature of the location fed by the intelligentcontrolled HVAC vent to temperatures of locations fed by otherintelligent controlled HVAC vents that have no externally settemperature goals; and if a result of the comparing indicates thetemperature of the location fed by the intelligent controlled HVAC ventis greater than a temperature of at least one of the locations fed bythe other intelligent controlled HVAC vents that have no externally settemperature goals, automatically decreasing airflow through theintelligent controlled HVAC vent.
 8. A method according to claim 2,wherein automatically recalculating the extent to which the intelligentcontrolled HVAC vent should be open comprises: comparing the temperatureof the location fed by the intelligent controlled HVAC vent totemperatures of locations fed by other intelligent controlled HVAC ventsthat have no externally set temperature goals; and if a result of thecomparing indicates the temperature of the location fed by theintelligent controlled HVAC vent is less than a temperature of at leastone of the locations fed by the other intelligent controlled HVAC ventsthat have no externally set temperature goals, automatically decreasingairflow through the intelligent controlled HVAC vent.
 9. A methodaccording to claim 2, wherein automatically recalculating the extent towhich the intelligent controlled HVAC vent should be open comprises:comparing temperatures of all locations fed by intelligent controlledHVAC vents that have no externally set temperature goals to ascertainwhich intelligent controlled HVAC vent that has no externally settemperature goal has a lowest temperature; comparing the temperature ofthe location fed by the intelligent controlled HVAC vent to the lowesttemperature; using the first information to ascertain whether theintelligent controlled HVAC vent that that has no externally settemperature goal and the lowest temperature is fully open; and if aresult of the comparings indicates (a) the intelligent controlled HVACvent that has no externally set temperature goal and the lowesttemperature is fully open and (b) the temperature of the location fed bythe intelligent controlled HVAC vent is greater than the lowesttemperature, automatically decreasing airflow through the intelligentcontrolled HVAC vent.
 10. A method according to claim 9, whereinautomatically decreasing the airflow comprises: calculating a differencebetween the temperature of the location fed by the intelligentcontrolled HVAC vent and a predefined temperature; and automaticallyclosing a damper of the intelligent controlled HVAC vent by an amountthat is a function of the difference.
 11. A method according to claim10, wherein automatically decreasing the airflow further comprises:calculating a duration the difference has existed; and automaticallyclosing the damper by an amount that is a function of the difference andthe duration.
 12. A method according to claim 2, wherein automaticallyrecalculating the extent to which the intelligent controlled HVAC ventshould be open comprises: comparing temperatures of all locations fed byintelligent controlled HVAC vents that have no externally settemperature goals to ascertain which intelligent controlled HVAC ventthat has no externally set temperature goal has a highest temperature;comparing the temperature of the location fed by the intelligentcontrolled HVAC vent to the highest temperature; using the firstinformation to ascertain whether the intelligent controlled HVAC ventthat has no externally set temperature goal and the highest temperatureis fully open; and if a result of the comparings indicates (a) theintelligent controlled HVAC vent that has no externally set temperaturegoal and the highest temperature is fully open and (b) the temperatureof the location fed by the intelligent controlled HVAC vent is less thanthe highest temperature, automatically decreasing airflow through theintelligent controlled HVAC vent.
 13. A method according to claim 12,wherein automatically decreasing the airflow comprises: calculating adifference between the temperature of the location fed by theintelligent controlled HVAC vent and a predefined temperature; andautomatically closing a damper of the intelligent controlled HVAC ventby an amount that is a function of the difference.
 14. A methodaccording to claim 13, wherein automatically decreasing the airflowfurther comprises: calculating a duration the difference has existed;and automatically closing the damper by an amount that is a function ofthe difference and the duration.
 15. A method according to claim 1,further comprising: ascertaining a dead band of all other locations fedby respective intelligent controlled HVAC vents that have no externallyset temperature goals; first comparing the temperature of the locationfed by the intelligent controlled HVAC vent to the dead band;ascertaining whether the intelligent controlled HVAC vent is fully open;wirelessly receiving second information indicating a respectivetemperature of a respective location fed by each other intelligentcontrolled HVAC vent that has no externally set temperature goal; secondcomparing the temperature of the location fed by the intelligentcontrolled HVAC vent to the second information; and if (a) a result ofthe first comparing indicates the temperature of the location fed by theintelligent controlled HVAC vent is outside the dead band and (b) theintelligent controlled HVAC vent is ascertained to be not fully open and(c) a result of the second comparing indicates the temperature of thelocation fed by the intelligent controlled HVAC vent is less than thetemperature of any location fed by another intelligent controlled HVACvent that has no externally set temperature goal, increasing the extentto which the intelligent controlled HVAC vent is open.
 16. A methodaccording to claim 1, further comprising: ascertaining a dead band ofall other locations fed by respective intelligent controlled HVAC ventsthat have no externally set temperature goals; first comparing thetemperature of the location fed by the intelligent controlled HVAC ventto the dead band; ascertaining whether the intelligent controlled HVACvent is fully open; wirelessly receiving second information indicating arespective temperature of a respective location fed by each otherintelligent controlled HVAC vent that has no externally set temperaturegoal; second comparing the temperature of the location fed by theintelligent controlled HVAC vent to the second information; and if (a) aresult of the first comparing indicates the temperature of the locationfed by the intelligent controlled HVAC vent is outside the dead band and(b) the intelligent controlled HVAC vent is ascertained to be not fullyopen and (c) a result of the second comparing indicates the temperatureof the location fed by the intelligent controlled HVAC vent is greaterthan the temperature of any location fed by another intelligentcontrolled HVAC vent that has no externally set temperature goal,increasing the extent to which the intelligent controlled HVAC vent isopen.
 17. A method according to claim 1, further comprising:ascertaining a dead band of all other locations fed by respectiveintelligent controlled HVAC vents that have no externally settemperature goals; first comparing the temperature of the location fedby the intelligent controlled HVAC vent to the dead band; wirelesslyreceiving second information indicating a respective temperature of arespective location fed by each other intelligent controlled HVAC ventthat has no externally set temperature goal; second comparing thetemperature of the location fed by the intelligent controlled HVAC ventto the second information; ascertaining whether at least one otherintelligent controlled HVAC vent that has no externally set temperaturegoal is fully open; if (a) a result of the first comparing indicates thetemperature of the location fed by the intelligent controlled HVAC ventis outside the dead band and (b) a result of the second comparingindicates the temperature of the location fed by the intelligentcontrolled HVAC vent is greater than temperatures of all locations fedby other intelligent controlled HVAC vents that have no externally settemperature goals and (c) at least one other intelligent controlled HVACvent that has no externally set temperature goal is ascertained to befully open, decreasing the extent to which the intelligent controlledHVAC vent is open.
 18. A method according to claim 1, furthercomprising: ascertaining a dead band of all other locations fed byrespective intelligent controlled HVAC vents that have no externally settemperature goals; first comparing the temperature of the location fedby the intelligent controlled HVAC vent to the dead band; wirelesslyreceiving second information indicating a respective temperature of arespective location fed by each other intelligent controlled HVAC ventthat has no externally set temperature goal; second comparing thetemperature of the location fed by the intelligent controlled HVAC ventto the second information; ascertaining whether at least one otherintelligent controlled HVAC vent that has no externally set temperaturegoal is fully open; if (a) a result of the first comparing indicates thetemperature of the location fed by the intelligent controlled HVAC ventis outside the dead band and (b) a result of the second comparingindicates the temperature of the location fed by the intelligentcontrolled HVAC vent is less than temperatures of all locations fed byother intelligent controlled HVAC vents that have no externally settemperature goals and (c) at least one other intelligent controlled HVACvent that has no externally set temperature goal is ascertained to befully open, decreasing the extent to which the intelligent controlledHVAC vent is open.
 19. A method according to claim 1, furthercomprising: ascertaining a dead band of all other locations fed byrespective intelligent controlled HVAC vents that have no externally settemperature goals; first comparing the temperature of the location fedby the intelligent controlled HVAC vent to the dead band; ascertainingwhether at least one intelligent controlled HVAC vent that has anexternally set temperature goal is fully open and has failed to achievethe externally set temperature goal; and if (a) a result of the firstcomparing indicates the temperature of the location fed by theintelligent controlled HVAC vent is within the dead band and (b) atleast one intelligent controlled HVAC vent that has an externally settemperature goal is ascertained: (1) to be fully open and (2) to havefailed to achieve the externally set temperature goal, decreasing theextent to which the intelligent controlled HVAC vent is open.
 20. Amethod according to claim 1, further comprising: ascertaining a deadband of all other locations fed by respective intelligent controlledHVAC vents that have no externally set temperature goals; firstcomparing the temperature of the location fed by the intelligentcontrolled HVAC vent to the dead band; ascertaining whether at least oneintelligent controlled HVAC vent is fully open; if (a) a result of thefirst comparing indicates the temperature of the location fed by theintelligent controlled HVAC vent is within the dead band and (b) nointelligent controlled HVAC vent is ascertained to be fully open,increasing the extent to which the intelligent controlled HVAC vent isopen.